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Understanding how habitat structure relates to reproductive performance of species can help identify what habitats are of the highest quality for a given species and thereby guide effective management. Here, we compared the influence of prey abundance and the amount of shelter area on the relationship between habitat and breeding performance. We focused on the forest‐dwelling northern goshawk Accipiter gentilis in an agroforestry system. Using structural equation modelling, we tested the associations between reproductive performance and three explanatory factors: habitat structure, abundance of food resources or levels of mobbing disturbance, and prey supply to the nest. Our results suggest that habitat structure influences reproductive performance through shelter rather than through prey abundance. During the study period, forested habitats in the breeding territories provided shelter to the goshawk, reducing disturbance by carrion crows Corvus corone, which acted as large, aggressive, social mobbers. Decreased disturbance increased prey supply to the nest, probably because it favored food accessibility and male goshawk foraging efficiency. Habitat was not significantly associated with quality of the breeders, both in terms of body size and seniority in the territories. Our findings suggest that reproductive performance, and therefore habitat quality, may depend more on sheltered access to food resources than on the amount of food available. Our observation that mobbers decrease predator foraging efficiency highlights the possibility of designing effective, socially acceptable predator management strategies to protect sensitive domestic prey. [ABSTRACT FROM AUTHOR]

Fecundity, the number of young produced by a breeding pair during a breeding season, is a primary component in evolutionary and ecological theory and applications. Fecundity can be influenced by many environmental factors and requires long‐term study due to the range of variation in ecosystem dynamics. Fecundity data often include a large proportion of zeros when many pairs fail to produce any young during a breeding season due to nest failure or when all young die independently after fledging. We conducted color banding and monthly censuses of Florida scrub‐jays (Aphelocoma coerulescens) across 31 years, 15 populations, and 761 territories along central Florida's Atlantic coast. We quantified how fecundity (juveniles/pair‐year) was influenced by habitat quality, presence/absence of nonbreeders, population density, breeder experience, and rainfall, with a zero‐inflated Bayesian hierarchical model including both a Bernoulli (e.g., brood success) and a Poisson (counts of young) submodel, and random effects for year, population, and territory. The results identified the importance of increasing "strong" quality habitat, which was a mid‐successional state related to fire frequency and extent, because strong territories, and the proportion of strong territories in the overall population, influenced fecundity of breeding pairs. Populations subject to supplementary feeding also had greater fecundity. Territory size, population density, breeder experience, and rainfall surprisingly had no or small effects. Different mechanisms appeared to cause annual variation in fecundity, as estimates of random effects were not correlated between the success and count submodels. The increased fecundity for pairs with nonbreeders, compared to pairs without, identified empirical research needed to understand how the proportion of low‐quality habitats influences population recovery and sustainability, because dispersal into low‐quality habitats can drain nonbreeders from strong territories and decrease overall fecundity. We also describe how long‐term study resulted in reversals in our understanding because of complications involving habitat quality, sociobiology, and population density. [ABSTRACT FROM AUTHOR]

Classical models predict that male fitness is based on resources monopolized and invested in reproduction, and/or on individual quality providing offspring with sexually attractive traits or viable genes. However, these factors are frequently correlated, making their relative influence on male fitness difficult to describe and quantify. We analysed the relative influence of the main features of the sedge warbler's Acrocephalus schoenobaenus breeding system, i.e. age, arrival date, territory quality, male sexual activity (song and polyterritorial behaviour), on males' mating success, fledging success and local recruitment. Results show that this species' breeding system involves three main paths: 1) earlier‐arriving males have higher mating success, regardless of territory quality, 2) the quality of territories pre‐empted by earlier males directly influences recruitment and 3) mating success is influenced by male sexual activity (polyterritorial behaviour), but an additional territory also affects recruitment directly. As arrival date plays a significant role in all the paths, the whole system seems to depend on male quality; although the benefits accruing to male fitness are obtained not only through sexual selection but also through resource monopolization. [ABSTRACT FROM AUTHOR]

Mating strategies are key components in the fitness of organisms, and notably in birds the occurrence of monogamy versus polygyny has attracted wide interest. We address this by a very comprehensive dataset (2899 breeding events spanning the years 1978–2019) of the white‐throated dipper Cinclus cinclus. Though the mating system of this species has been regarded as generally monogamous, we find that 7% of all breeding events were performed by polygynous males (approximately 15% of all pairs). The fraction of polygyny has been stable over the entire study period irrespective of population size. The assumption that polygyny is most common at low population density was not supported. Surprisingly, there was no difference between polygynous and monogamous males with regard to the quality of the territories they inhabited, ranked according to their overall frequency of use. The most common age group, first‐year breeders, dominated among monogamous males, while among polygynous males second‐year breeders were most common, followed by third and first‐year breeders. The primary females were in general older than females mated to monogamous males, also when controlled for their general frequency in the population. The majority of the two females mated to a polygynous male, bred in the vicinity of each other. The probability for a male to be involved in polygyny more than once, was significantly higher than by chance, suggesting phenotypic quality differences among males. [ABSTRACT FROM AUTHOR]

Classical models predict that male fitness is based on resources monopolized and invested in reproduction, and/or on individual quality providing offspring with sexually attractive traits or viable genes. However, these factors are frequently correlated, making their relative influence on male fitness difficult to describe and quantify. We analysed the relative influence of the main features of the sedge warbler's Acrocephalus schoenobaenus breeding system, i.e. age, arrival date, territory quality, male sexual activity (song and polyterritorial behaviour), on males' mating success, fledging success and local recruitment. Results show that this species' breeding system involves three main paths: 1) earlier‐arriving males have higher mating success, regardless of territory quality, 2) the quality of territories pre‐empted by earlier males directly influences recruitment and 3) mating success is influenced by male sexual activity (polyterritorial behaviour), but an additional territory also affects recruitment directly. As arrival date plays a significant role in all the paths, the whole system seems to depend on male quality; although the benefits accruing to male fitness are obtained not only through sexual selection but also through resource monopolization.

Abstract Mating strategies are key components in the fitness of organisms, and notably in birds the occurrence of monogamy versus polygyny has attracted wide interest. We address this by a very comprehensive dataset (2899 breeding events spanning the years 1978–2019) of the white‐throated dipper Cinclus cinclus. Though the mating system of this species has been regarded as generally monogamous, we find that 7% of all breeding events were performed by polygynous males (approximately 15% of all pairs). The fraction of polygyny has been stable over the entire study period irrespective of population size. The assumption that polygyny is most common at low population density was not supported. Surprisingly, there was no difference between polygynous and monogamous males with regard to the quality of the territories they inhabited, ranked according to their overall frequency of use. The most common age group, first‐year breeders, dominated among monogamous males, while among polygynous males second‐year breeders were most common, followed by third and first‐year breeders. The primary females were in general older than females mated to monogamous males, also when controlled for their general frequency in the population. The majority of the two females mated to a polygynous male, bred in the vicinity of each other. The probability for a male to be involved in polygyny more than once, was significantly higher than by chance, suggesting phenotypic quality differences among males.

Territory quality shapes population dynamics and has conservation implications for territorial species. Yet, quantifying territory quality using different measures can yield conflicting results, particularly if territory selection is non-ideal, thus challenging the understanding of territory quality. We used a 25-year population study of spotted owls (Strix occidentalis) occupying 72 territories to evaluate five commonly used demographic- and occupancy-based measures of territory quality: occupancy rate, annual apparent survival rate, territory fitness, mean annual reproductive rate, and total reproductive output. To do so, we evaluated pairwise relationships between measures of territory quality and assessed the extent to which spotted owls selected territories based on their potential to promote fitness. Measures of territory quality were generally positively correlated. Notably, however, territory occupancy explained less than half of the variation (R2 = 0.37) in territory fitness (the expected fitness of territory holders). Non-ideal patterns in territory occupancy were the result of weak linkages between the likelihood of vacant territories becoming colonized and their fitness potential, particularly their capacity to promote reproduction. Imperfect territory colonization was likely the product of the spotted owl’s strong site fidelity to even low-fitness territories and constraints on the ability of dispersing individuals to locate high quality territories. Mismatches emerging from non-ideal colonization have important conservation implications because populations may benefit more from habitat restoration at low fitness-high occupancy territories and more from conspecific attraction measures at high fitness-low occupancy territories. Our findings for spotted owls were reasonably consistent with broad patterns observed for other species in previous studies, but the strength of associations between pairs of territory quality measures often varied considerably, suggesting that species-specific assessments of patterns in territory quality are important. Finally, when practical, examination of the ecological processes shaping multiple measures of territory quality will benefit the study and conservation of territorial species.

Abstract Whether an individual disperses or remains site‐faithful between breeding seasons can have important impacts on individual fitness and population dynamics. While several studies have identified factors influencing the probability of breeding dispersal, the consequences of dispersal are much less certain, particularly over an individual’s lifetime. Here, we use 81 cases (13 paired and 55 single dispersals) of breeding dispersal across 55 yr of breeding and re‐sighting data from an individually marked population of Canada jays (Perisoreus canadensis) at the southern edge of their range in Algonquin Provincial Park, Ontario to determine both the short‐ (year after dispersal) and long‐term (lifetime) consequences of breeding dispersal. In the year following dispersal, adults had larger brood sizes and higher nest success compared to the year prior to dispersal. However, when adults dispersed during the fall/winter, they had significantly later lay dates and lower rates of nest success than adults that dispersed during the summer. Additionally, most breeders dispersed to territories of higher quality and individuals that dispersed to a territory of lesser quality experienced lower rates of nest success. Importantly, individuals that dispersed at least once in their lifetime produced an average of 2.7 more young and recruited an average of 0.9 more juveniles into the population compared to individuals that remained site‐faithful. Our study provides rare evidence of both the short‐ and long‐term benefits of breeding dispersal in Canada jays and demonstrates how the timing of dispersal can also have consequences for individual reproductive performance.

Whether an individual disperses or remains site‐faithful between breeding seasons can have important impacts on individual fitness and population dynamics. While several studies have identified factors influencing the probability of breeding dispersal, the consequences of dispersal are much less certain, particularly over an individual's lifetime. Here, we use 81 cases (13 paired and 55 single dispersals) of breeding dispersal across 55 yr of breeding and re‐sighting data from an individually marked population of Canada jays (Perisoreus canadensis) at the southern edge of their range in Algonquin Provincial Park, Ontario to determine both the short‐ (year after dispersal) and long‐term (lifetime) consequences of breeding dispersal. In the year following dispersal, adults had larger brood sizes and higher nest success compared to the year prior to dispersal. However, when adults dispersed during the fall/winter, they had significantly later lay dates and lower rates of nest success than adults that dispersed during the summer. Additionally, most breeders dispersed to territories of higher quality and individuals that dispersed to a territory of lesser quality experienced lower rates of nest success. Importantly, individuals that dispersed at least once in their lifetime produced an average of 2.7 more young and recruited an average of 0.9 more juveniles into the population compared to individuals that remained site‐faithful. Our study provides rare evidence of both the short‐ and long‐term benefits of breeding dispersal in Canada jays and demonstrates how the timing of dispersal can also have consequences for individual reproductive performance. [ABSTRACT FROM AUTHOR]

Human activity around the globe is a growing source of selection pressure on animal behavior and communication systems. Some animals can modify their vocalizations to avoid masking from anthropogenic noise. However, such modifications can also affect the salience of these vocalizations in functional contexts such as competition and mate choice. Such is the case in the well-studied Nuttall's white-crowned sparrow (Zonotrichia leucophrys nuttalli), which lives year-round in both urban San Francisco and nearby rural Point Reyes. A performance feature of this species' song is salient in territorial defense, such that higher performance songs elicit stronger responses in simulated territorial intrusions; but songs with lower performance values transmit better in anthropogenic noise. A key question then is whether vocal performance signals male quality and ability to obtain high quality territories in urban populations. We predicted white-crowned sparrows with higher vocal performance will be in better condition and will tend to hold territories with lower noise levels and more species-preferred landscape features. Because white-crowned sparrows are adapted to coastal scrub habitats, we expect high quality territories to contain lower and less dense canopies, less drought, more greenness, and more flat open ground for foraging. To test our predictions, we recorded songs and measured vocal performance and body condition (scaled mass index and fat score) for a set of urban and rural birds (N = 93), as well as ambient noise levels on their territories. Remote sensing metrics measured landscape features of territories, such as drought stress (NDWI), greenness (NDVI), mean canopy height, maximum height, leaf area density (understory and canopy), slope, and percent bare ground for a 50 m radius on each male territory. We did not find a correlation between body condition and performance but did find a relationship between noise levels and performance. Further, high performers held territories with lower canopies and less dense vegetation, which are species-preferred landscape features. These findings link together fundamental aspects of sexual selection in that habitat quality and the quality of sexually selected signals appear to be associated: males that have the highest performing songs are defending territories of the highest quality.

Natal sex‐ratio variation is a central concept in population demography. When males and females are equally costly to rear, the population sex ratio should be 1:1, but if they differ in cost, more of the cheaper sex should be produced. According the age dependent sex ratio hypothesis, younger breeders should produce more chicks of the cheaper sex. On the other hand, the environmental sex determination hypothesis suggests that parents in poor conditions (scarce food and low‐quality territories) tend to produce more of the cheaper sex. To test hypotheses on adaptive sex ratio, we studied the booted eagle Aquila pennata, a raptor with marked sexual dimorphism, with females larger than males. We sexed 174 nestlings from 121 broods in 1996–2000 to study hatching and fledgling sex ratios. We did not find deviations of the 1:1 sex ratio at the population level during the length of the whole study period or on a yearly basis. Sex ratio was affected by age of the breeders, but not by territory quality (average productivity), quality of year, nearest nest distance or number of breeding pair in the population. Older breeders raised more females (i.e. the expensive sex), supporting the age dependent sex ratio hypothesis. In long‐lived species, older breeders tend to occupy better quality territories than younger ones, confounding some of the commonly used surrogates of territory quality, like frequency of occupation or year of first occupation; results obtained from observational studies should be interpreted with caution. We discuss alternative approaches and different scenarios that could provide new insight into the study of factors that influence sex ratio deviations in vertebrates. [ABSTRACT FROM AUTHOR]

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Parental and territory quality are often correlated in territorial birds, and both factors influence the resources allocated to offspring. Surprisingly, the relative contribution of these two components of variation in parental investment remains obscure. We experimentally decoupled the normal covariation between parental quality and territory quality to test the hypothesis that territory quality influences female prenatal and postnatal reproductive allocation. Territories were categorized into low-, intermediate-, and high-quality based on fledging success of nests over the previous 6 years (nesting sites are fixed in space).To decouple covariation between territory quality and individual quality, nestbox entrance size was increased on high-quality territories and left small on poor-quality sites because house wrens (Troglodytes aedon) prefer small over large entrances to their nest sites. We found a significant prenatal effect of territory quality on nestling provisioning: when reared on intermediate-quality territories, nestlings hatching from eggs produced on low-quality territories were provisioned at a higher rate than those hatching from eggs produced on high-quality territories. We propose that the increased provisioning was brought about by increased nestling begging mediated by a maternally derived compound, such as corticosterone, transferred to the eggs of stressed females in poor-quality habitat. [ABSTRACT FROM AUTHOR]

The barn swallow, Hirundo rustica, is a model species for studying sexual selection, particularly female mate choice. Although there have already been several reviews of female mate choice and its geographic variation in this species, all of them have focused on secondary sexual characteristics. Here, for better understanding of the general pattern of female mate choice and their influence on male phenotype, I review all of the female mate choice criteria ever reported in the barn swallow, emphasizing the importance of relatively inconspicuous male traits. These include resources defended or provided by males, such as territory and paternal investment. In addition, females prefer a nestling-like vocalization, enticement call, which is particularly noteworthy because females prefer immature calls. This pattern contrasts with female choice based on secondary sexual characteristics, in which more mature, elaborate male traits are almost always favored. Nestling-like male traits are widespread, and thus female avoidance of, rather than preference for, mature forms might be common. In addition to selection on the target trait itself, these resources and nestling-like male traits would also matter in understanding the evolution of the overall male phenotype and its geographic variation, due to the interrelationships among male target traits and those among female mate preferences. Female preferences for inconspicuous traits are highly dependent on ecological factors such as nest predation pressure, and thus overall male phenotype including secondary sexual characteristics might be more predictable than previously thought. Future studies should focus on not only conspicuous secondary sexual characteristics but inconspicuous male traits. [ABSTRACT FROM AUTHOR]

In territorial species, females are often attracted by high-qualityterritories, which are expected to be owned by males that successfully won competition with other males. Because morphological and behavioral traits frequently influence males’ combat success, these parameters may be used by females to assess the male (and associated territory) quality. In the present study, we tested the hypothesis that organismal traits in dominant males of the lizard Tropidurus torquatus are associated with the quality of the territory owned. After characterizing the territories occupied, we used a discriminant analysis to test if morphological and behavioral traits of the dominant male predict the quality of the territory owned. High-quality territories were characterized by a larger number of refuges, shorter distances among shelters and a well-defined harem, in comparison with low-quality territories. Organismal traits predicted with 100% accuracy the type of the territory owned: high-quality territories were associated with larger males that had longer heads, while males occupying lowquality territories exhibited more head displays, traveled larger distances and ran slightly slower than those associated with high-quality territories. We discuss possibleimplications of territory quality and male traits for reproductive success in Tropidurus torquatus.

Although territory selection is likely to be under strong natural selection, in many cases it might be impossible for individuals to judge territory quality directly in terms of fitness return. Thus, animals often rely on some indirect environmental cues in territory assessment and they may not be able to make optimal settlement decisions when subjected to a novel environment. The aim of this study was to investigate adaptiveness of territory selection in a newly established urban population (Łódź, central Poland) of a waterbird, the Eurasian coot Fulica atra. For this purpose, we correlated occupancy rate of urban breeding territories over a 7-year period with basic fitness-related traits of coots. We found that the average number of fledglings raised by Eurasian coots increased with territory occupancy, indicating that birds were able to reliably judge territory quality and to choose nest sites which maximized their reproductive success. This conclusion was supported by the fact that in the process of territory selection coots used a set of habitat cues important for successful nest concealment and brood safety. In contrast, we found that coots showed no preferences for territories which provided easy access to anthropogenic food resources (via public feeding of waterbirds) and there was no relationship between condition of adult birds and territory occupancy, suggesting that either: (1) brood safety was a more important component in territory assessment than food availability, or (2) birds were unable to reliably judge food resources in a novel urban landscape. [ABSTRACT FROM AUTHOR]

Experiments designed to quantify the effects of increasing numbers of carers on levels of offspring care are rare in cooperative breeding systems, where offspring are reared by individuals additional to the breeding pair. This paucity might stem from disagreement over the most appropriate manipulations necessary to elucidate these effects. Here, we perform both carer removal and brood enhancement experiments to test the effects of numbers of carers and carer:offspring ratios on provisioning rates in the cooperatively breeding chestnut-crowned babbler (Pomatostomus ruficeps). Removing carers caused linear reductions in overall brood provisioning rates. Further analyses failed to provide evidence that this effect was influenced by territory quality or disruption of group dynamics stemming from the removals. Likewise, adding nestlings to broods caused linear increases in brood provisioning rates, suggesting carers are responsive to increasing offspring demand. However, the 2 experiments did not generate quantitatively equivalent results: Each nestling received more food following brood size manipulation than carer removal, despite comparable carer:offspring ratios in each. Following an at-hatching split-design cross-fostering manipulation to break any links between prehatching maternal effects and posthatching begging patterns, we found that begging intensity increased in larger broods after controlling for metrics of hunger. These findings suggest that manipulation of brood size can, in itself, influence nestling provisioning rates when begging intensity is affected by scramble competition. We highlight that carer number and brood size manipulations are complimentary but not equivalent; adopting both can yield greater overall insight into carer effects in cooperative breeding systems. [ABSTRACT FROM AUTHOR]

Territorial activities of a lycaenid butterfly, C hrysozephyrus smaragdinus, were observed throughout its adult season to investigate the territorial dynamics. The territories occupied earlier in the season were abandoned later than later-occupied territories, indicating that the site preference of male C . smaragdinus was largely maintained during the adult season. Three indexes of territory quality based on animal preference, occupation duration ( OD), initial occupation date ( IOD) and the number of contests ( NOC), were highly correlated. Therefore, these preference-based indexes are consistent and reliable, although they are indirect estimates of benefits obtained from territories. Males arriving at territory sites early in the season were more likely to hold territories of better quality when NOC was used as the index of territory quality. The positive relationship between territory quality and male arrival date is congruent with the result of a previous study showing that early comers tend to hold a territory whereas late comers do not. However, male arrival date was not related to territory quality when OD or IOD was used as an index of territory quality. One possible reason for this apparent discrepancy is that the coefficient of variation of NOC is larger than those of OD and IOD, and therefore NOC could evaluate territory quality more quantitatively than the other two indexes. To date, studies of territoriality in butterflies have not considered the quality of territories. More studies considering the quality of territories will provide new insights into butterfly territoriality. [ABSTRACT FROM AUTHOR]

In precocial birds, adults select breeding areas using cues associated with habitat characteristics that are favorable for nesting success and chick survival, but there may be tradeoffs in habitat selection between these breeding stages. Here we describe habitat selection and intra-territory movements of 53 Piping Plover ( Charadrius melodus) broods (320 observations) during the 2007-2008 breeding seasons on mainland- and island-shoreline habitats at Lake Sakakawea, North Dakota, USA. We used remotely sensed habitat characteristics to separately examine habitat selection and movements at two spatiotemporal scales to account for potential confounding effects of nest-site selection on brood-rearing habitat used. The scales used were (1) the entire brood-rearing period within available brood-rearing areas and (2) 2-day observation intervals within age-specific discrete habitat selection choice sets. Analyses at both scales indicated that broods selected areas which were non-vegetated, moderately level, and nearer to the shoreline. Rate of brood movement increased with age up to 5 days, then stabilized; broods that hatched >50 m away from the shoreline moved toward the shoreline. Brood movements were greater when they were in vegetated areas, when the brood-rearing area was of greater topographic complexity, and when broods aged 6-25 days were further away from the shoreline. Using inferences from our results and those of previously published work, we postulate how a potential tradeoff in habitat selection between nesting and brood-rearing can contribute to an ecological trap in a novel habitat. This work, in the context of published works, suggests that plover breeding habitat is a complex of both nesting and brood-rearing habitats and provides a basis for making remotely sensed abundance estimates of suitable breeding habitat for Piping Plovers. [ABSTRACT FROM AUTHOR]

Life history theory predicts that individuals should maximize lifetime reproductive success ( LRS) by breeding as soon as they reach sexual maturity, yet many species delay breeding, either because there are insufficient available mates or breeding sites, or because delayed breeding yields higher LRS. Accipitriform species, such as Cooper's Hawk Accipiter cooperii, exhibit both delayed breeding and delayed plumage maturation. However, in certain circumstances, first-year females in non-definitive plumage do breed and apparently compete with older females for high-quality breeding territories. We predicted that these young females are at a competitive disadvantage compared with older females and that older females would have both higher reproductive success and be able to acquire higher quality nesting territories. We conducted brood counts and measured prey delivery rates by male Cooper's Hawks in an expanding urban population located in Albuquerque, New Mexico ( USA), to assess our prediction. We found that older females had higher reproductive success, fledging 1.6 more offspring than younger females, and that they occupied territories where males provisioned at higher rates of 0.37 more prey items per 2-h period. Our results showed that older females fared better than first-year females but it is unclear if this is the result of passive or active competition. Older females initiated nesting 14.3 days sooner than first-year females and thus may have filled vacant, high-quality territories before first-year females began seeking mates. Additionally, first-year females were never observed persistently to confront older females for breeding territories, but they did actively compete against each other. First-year females may defer to older females who, in a direct competitive interaction, would be most likely to prevail. Thus, delayed plumage maturation in Cooper's Hawks may serve to focus competition for nesting territories within age classes. [ABSTRACT FROM AUTHOR]

There is growing evidence that the fitness of birds in temperate zones depends strongly on the match between the timing of breeding and local phenology. We have analysed data collected from a 15-year study on a Sedge Warbler ( Acrocephalus schoenobaenus) population in its natural habitat. The highly skewed distribution of arrival dates of males indicated that they competed intensely to be the earliest arrivals. The distribution of mating dates, unlike arrival dates, was not skewed, rather it formed a bell-shaped distribution. Because females arrived much later, they could not base their mating choices on the arrival dates of males. Females, however, could use male song repertoire, a trait we found to be correlated with male arrival date. Double-brooded females mated early in the season, exactly within the peak of mating date distribution. Polygynous females, on the other hand, mated later in the season, choosing high-quality older males which had arrived significantly earlier. Male territory quality did not differ between double-brooded and polygynous females, nor did the quality of the territories occupied by an individual female change during her lifetime. Although longer lifespan and double-brooding influenced a female's fitness over the course of her lifetime, polygyny had no significant effect. We conclude that Sedge Warbler females do not compete for territorial resources, but they do prefer to mate with high-quality early-arriving males. Polygyny is an effective strategy used by females to compensate for their late arrival and breeding onset, since they pair with high-quality males. [ABSTRACT FROM AUTHOR]

The link between resource abundance, dispersion and cooperative breeding in mammals has been a topic of much debate among ecologists. The giant otter social system is facultatively cooperative. Extended families inhabit home ranges where only a dominant pair breeds, and other family members assist with cub defence and food provision. But this system can be affected by local ecology. In the floodplain of the Manu River, in Manu National Park, Peru, oxbow lakes are patchily distributed and form the resource-rich cores, or territories, of giant otter family home ranges. We present data from a long-term study at this site, linking territory size variability to the composition of resident giant otter groups and their reproductive success. Territory size predicts group structure; both the size of groups and the number of post-emergence cubs are positively correlated to the total lake area within the group territory. Territories with small lake areas (likely to be poor territories) often support only a pair, and the pair may not breed successfully every year. Cubs are more likely to survive in years when more non-breeding adults are present at the time of emergence. However, there may be a negative effect on survival where more non-breeding adults are present in the subsequent year. Finally, cubs produced in larger territories are more likely to disperse and breed successfully away from the natal territory. We conclude that giant otter societies are likely shaped by the spatial dispersion of lakes, and food abundance and dispersion within these rich patches. [ABSTRACT FROM AUTHOR]

Female mate preferences for male traits and resource characteristics affect trait evolution and diversification. Here, we test the effects of male body traits and territory characteristics on within-population female preferences and on population-assortative mating in the cichlid Tropheus moorii. Within-population preferences of females were independent of male body size, coloration and territory size but were strongly dependent on territory quality and co-varied with male courtship activity. Courtship activity of individual males was contingent on the quality of their assigned territory, and therefore, courtship may not only indicate intrinsic male quality. On the basis of these results we suggest that female preferences for high-quality territories reinforce the outcome of male-male competition and ensure male mating success. Mating preferences of females for males of their own color variant (ascertained in a previous experiment) were not overturned when males of another color variant were presented in a superior territory, indicating that within- and between-population mate preferences of females depend on different cues. [ABSTRACT FROM AUTHOR]

The European barn swallow, Hirundo rustica rustica, is a model system of female mate choice for indirect benefits. Its long tail, which is the target of female mate choice, is positively related to the genetic quality of males, whereas direct benefits in terms of territory quality and paternal care are unimportant in the choice of long-tailed males. However, the situation may differ in other subspecies where male ornaments other than tail length are elaborate and appear to be the main target of female choice. Here we studied whether throat colouration, a sexually selected trait, provides direct benefits in terms of territory quality and parental care in a population of Japanese barn swallows, H. r. gutturalis, which have short tails and large throat patches. We compared dyads of males occupying neighbouring territories to study the relationship between male ornamentation and territory quality in our sparse population. Males with higher quality territories had more colourful throat patches than males with lower quality territories, indicating a positive relationship between male throat colouration and the quality of their territory. In contrast, male feeding rate decreased with increasing colourfulness of male throat patch without confounding with female feeding rate. These results are consistent with previous studies showing a positive association between plumage colouration and testosterone levels. The trade-off between the two direct benefits of mate choice, i.e., territory quality and paternal care, can explain sexual selection for colourful throat patches rather than long tails in our sparse outdoor population, a typical breeding habitat in Japan, whereas it predicts a reverse pattern in dense indoor populations as found in Europe. [ABSTRACT FROM AUTHOR]

The costs of reproduction are an important constraint that shapes the evolution of life histories, yet our understanding of the proximate mechanism(s) leading to such life-history trade-offs is not well understood. Oxidative stress is a strong candidate measure thought to mediate the costs of reproduction, yet empirical evidence supporting that increased reproductive investment leads to oxidative stress is equivocal. We investigated whether territory quality and offspring provisioning increase oxidative stress in male snow buntings ( Plectrophenax nivalis) using a repeated sampling design. We show that arrival oxidative stress is not a constraint on territory quality or the number of offspring fledged. Nevertheless, owners of higher-quality territories experienced an oxidative cost, with this cost increasing more rapidly in younger males. Males that provisioned offspring at a high rate also experienced increased oxidative stress. Together, these findings support the potential role of oxidative stress in mediating life-history trade-offs. Future work should consider that reproductive workload is not limited to offspring care, and other activities - including territory defence - may contribute significantly to the costs of reproduction. [ABSTRACT FROM AUTHOR]

While the relationship between aggression and resource value in competitions for discrete resources is well established, the relationship between aggression and territory quality is less well understood. Territoriality imposes spatial structure on social interactions: if spatial heterogeneity in habitat quality leads to clustering of high- and low-quality territories, and if consistently more aggressive individuals are more likely to obtain higher-quality territories, the resulting clusters of territory holders of similar aggression are likely to influence a wide array of social dynamics in territorial species, particularly when aggressive behaviour is consistently associated with variation in other behaviours, such as boldness. Using 8years of historical nesting data in a northeastern population of song sparrows, we here determine (1) whether historical nesting success (defined both as clutch size and survival) is spatially clustered; and (2) whether aggression or boldness in first-year territorial males is correlated with the historical clutch size or nest survival of each male''s territory. We found significant clustering of both predation risk and large clutch sizes, even when controlling for the identities of historical territory owners. The aggressive behaviour of new territorial males was correlated with historical clutch size, but not with historical nest survival; in contrast, boldness was not correlated with either historical clutch size or nest survival. Thus, spatial variation in habitat quality is correlated with territorial aggression, but territory holders may either prioritize or be unable to assess all variables contributing to territory quality. In addition, a boldness-aggression syndrome does not necessarily result in both behaviours covarying with territory quality. [Copyright &y& Elsevier]

Territory fidelity defines a process in which individuals reoccupy a territory during different reproductive periods. In this study, we used generalized linear mixed models to analyse the territory fidelity of the Booted Eagle Hieraaetus pennatus in relation to different variables of the individual (previous breeding success, sex, mate switching and experience) and territory (average productivity in the territory). The data used refer to 86 eagles (48 females and 38 males) individually identified between 1996 and 2009 in a Special Protection Area of 'Sierras de Burete, Lavia y Cambrón' (Murcia, southeastern Spain). The results indicated that the breeding success in the previous year had significant effects on territory fidelity. The probability of reoccupation in cases of reproductive success in the previous year was 0.73, whereas in cases of reproductive failure, the probability of reoccupation in the following year was 0.41. Models which relate territory fidelity to biological variables of the individual (sex, mate switching and experience) and habitat quality were not significant. In conclusion, Booted Eagles show territory fidelity following the 'win-stay:lose-switch' rule, which suggests that individuals are able to assess their previous reproductive experience to decide whether or not to return to the same territory the following year. [ABSTRACT FROM AUTHOR]

The article presents a study to examine the correlation between natal dispersal distances of a population of Swainson's hawk monitored from 1979 to 2010 in northern California. It examines the effects of sex, number of offspring fledged, population density, primary productivity around a nest site and annual trends on dispersal from the natal site to the breeding site. Results show no correlation between natal dispersal distance and lifetime reproductive success of the hawks.

Abstract: Patterns of territory selection and sources of variation for reproductive performance in a Blue Tit Cyanistes caeruleus population breeding in nest-boxes during years 2007 and 2008 in a holm oak forest are analyzed. Territory selection has been assessed as a function of two fixed effect factors: territory location (peripheral vs. interior in the nestbox patch) and nestbox type (entrance hole: 26 mm vs. 32 mm). Breeding density was independent of these factors. Pairs nesting in periphery nest-boxes and in small-holed nestboxes owned territories bigger than those nesting in interior and large-holed nestboxes, respectively. The breeding traits studied were laying date, clutch size, hatching success, fledgling success and breeding success. Egg laying was earlier in periphery territories and small-holed nestboxes. Between-year variation was a factor significantly affecting to all breeding traits. Clutch size declines in late clutches. Hatching success was higher in territories with more tree density. Although egg laying started earlier in some territories, the mean breeding success was similar in all of them. However, territories with the greatest contribution of individuals to the population were those with small-holed nestboxes. Breeding success in successful pairs had a tendency to be higher in pairs with late clutches and in those nesting in interior territories with large-holed nestboxes. Both decreased breeding success and total breeding failure were much more important in the second breeding year than in the first one. The high breeding density of Blue Tit, favored by the experimental design of nestbox plot, did not suggest significant variation between territories in terms of breeding success achieved. Implications for nestbox management are discussed. [Copyright &y& Elsevier]

Abstract: In countries with high human populations, using agricultural areas as multifunctional systems to produce food for humans and retain wildlife may be an efficient conservation strategy for many species. Inclusion of natural habitat and species requirements on agricultural landscapes explicitly into planning processes are precluded by lack of information on drivers of species persistence. Climate change is an additional emerging complexity, and adaptation plans for agricultural landscapes are biased towards intensification to secure long-range food production. I examine the conservation potential of an agricultural landscape in two districts of Uttar Pradesh, north India where agricultural intensification and altered rainfall patterns are predicted to occur. I assess stressors affecting breeding success over eight years of two large waterbirds of conservation concern – Sarus Cranes and Black-necked Storks. Both species had high breeding success that improved with total rainfall and more wetlands in breeding territories. Agricultural and township expansions deteriorated territory quality and reduced breeding success. Sarus Crane populations were predicted to decline relatively rapidly if development activities continued to displace breeding pairs. Black-necked Storks appeared resilient over the long-term notwithstanding reduced breeding success in low-rainfall years. Waterbird nesting habitats (wetlands and trees) were retained in Uttar Pradesh as community lands by villages and by state government via legal provisions suggesting the utility of multiple conservation approaches. Incorporating species requirements explicitly, alongside traditional land use practices conducive for habitat conservation, into adaptation planning and conservation policy will be necessary to retain long-term multifunctionality of such agricultural landscapes. [Copyright &y& Elsevier]

A territorial male can shift the location of its territory from year to year in order to increase its quality. The male can base its decision on environmental cues or else on its breeding experiences (when territory shift is caused by breeding failure in previous seasons). We tested these possible mechanisms of territory choice in the sedge warbler ( Acrocephalus schoenobaenus), a territorial migrating passerine that occupies wetlands. This species bases its territory choices on an environmental cue: tall wetland vegetation cover. We found that the magnitude of territory quality improvement between seasons (measured as the area of tall wetland vegetation) increased throughout the early stages of a male's breeding career as a result of territory shifts dependent on the earliness of arrival. The distance the territory was shifted between seasons depended negatively on the previous year's territory quality and, less clearly, on the previous year's mating success. On the other hand, previous mating or nesting success had no influence on territory quality improvement between seasons as measured in terms of vegetation. The results imply that tall wetland vegetation is a long-term, effective environmental cue and that a preference for territories in which this type of landcover prevails has evolved into a rigid behavioral mechanism, supplemented by short-term individual experiences of breeding failure. [ABSTRACT FROM AUTHOR]

The article discusses a study on tawny owls to determine whether there are differences in territory choice between the young and old males and if these difference reflect territory quality and whether the relationships between territory choice and fledgling production show senescence patterns in old male tawny owls. Twenty two nest-box colonies for breeding tawny owls were found in a mixed oak/hornbeam/beech Quercus-Carpinus-Fagus forest in Budapest, Hungary. It concludes that the differences in territory choice between the high and low altitude range reflected territory quality with males having higher reproductive success at lower elevations.

In this paper, we study proximate causes and consequences of breeding dispersal and divorce in a Mediterranean blue tit Cyanistes caeruleus population. We attempt to evaluate the primacy of mate and territory quality in the decision making of birds. In females, the fidelity to their old territories was dependent on how they did in the previous year. We found differences in hatching success and fledging success between females that dispersed and those that did not. In particular, dispersal distance was negatively correlated with hatching success in the preceding breeding season. Dispersed females experienced a gain in terms of hatching success and increased productivity in comparison with those that retained their former mate. Both females and males improved the quality of their breeding site after dispersal. We also found evidence that divorce is adaptive for at least one pair member because adult females (but not juveniles) enhanced their breeding performance after the breakup. Such improvement was also observed when restricting the analyses to only those individuals that did not change territory, suggesting that these benefits not only accrue through the acquisition of better territories but advantages derived from pairing with a higher rank male (mate effects per se) could also be important. Our results suggest that 1) both dispersal and divorce can be regarded as adaptive decisions, 2) females play an active role in pair-bond maintenance, and 3) the intense competition for good nesting sites drives the observed high divorce rate (63%) reinforcing the view that breakups could be a side effect derived from the female’s attempt to improve their breeding place. [ABSTRACT FROM PUBLISHER]

Offspring delayed dispersal is the principal mechanism leading to formation of kin-based societies. It has been suggested that parents promote offspring philopatry by providing them with preferential access to the food resources of the territory and that parental tolerance may be affected by territory quality. However, few studies have addressed this hypothesis in kin-living vertebrate species. Here, we show that in cooperative breeding groups of carrion crows ( Corvus corone corone) containing retained offspring and immigrants, dominant breeding males behaved nepotistically on an experimental source of food by (1) attacking immigrants with more frequency and intensity than offspring and (2) associating preferentially with their offspring on the feeding spot and sharing food with them. This parental facilitation allowed the offspring to spend more time feeding than higher-rank immigrants. We also found that a year-round experimental food supplementation neither increased breeding males' tolerance nor relented the overall aggressiveness in the groups. This indicates that higher natal philopatry observed on fed territories compared to unfed ones is not a consequence of a more benign social environment. Rather, it suggests that offspring value territory resource wealth and adjust the timing of dispersal accordingly. [ABSTRACT FROM AUTHOR]

The ecological conditions leading to delayed dispersal and helping behavior are generally thought to follow one of two contrasting scenarios: that conditions are stable and predictable, resulting in young being ecologically forced to remain as helpers (extrinsic constraints and the habitat saturation hypothesis), or that conditions are highly variable and unpredictable, leading to the need for helpers to raise young, at least when conditions are poor (intrinsic constraints and the hard life hypothesis). We investigated how variability in ecological conditions influences the degree to which helpers augment breeder fitness in the cooperatively breeding acorn wood-pecker (Melanerpes formicivorus), a species in which the acorn crop, territory quality, and prior breeding experience all vary in ways that have important effects on fitness. We found that the relationship between ecological conditions and the probability that birds would remain as helpers was variable but that helpers generally yielded greater fitness benefits when ecological conditions were favorable, rather than unfavorable, for breeding. These results affirm the importance of extrinsic constraints to delayed dispersal and cooperative breeding in this species, despite its dependence on a highly variable and unpredictable acorn crop. Our findings also confirm that helpers can have very different fitness effects, depending on conditions, but that those effects are not necessarily greater when breeding conditions are unfavorable. [ABSTRACT FROM AUTHOR]

Abstract: Testosterone produced by the gonads is a primary mediator of seasonal patterns of territoriality and may directly facilitate territorial behavior during an encounter with a potential intruder. Costs and benefits associated with territoriality can vary as a function of habitat, for example through differences in resource distribution between areas occupied by different individuals. We investigated behaviors in response to simulated territorial intrusions (hereafter territorial behaviors) in urban (Phoenix, Arizona) and nearby desert populations of two Sonoran Desert birds (Curve-billed Thrasher and Abert''s Towhee). We also examined the degree to which these behaviors are mediated by testosterone (T) and the adrenal steroid, corticosterone (CORT), which can interact with T in territorial contexts. In both species, urban birds displayed more territorial behaviors than their desert conspecifics, but this difference was not associated with variation in either plasma total or in plasma free (i.e., unbound to binding globulins) T or CORT. In addition, neither plasma T nor plasma CORT changed as a function of duration of the simulated territorial intrusion. Urban Abert''s Towhees displayed more territorial behaviors in areas where their population densities were high than in areas of low population densities. Urban Curve-billed Thrashers displayed more territorial behaviors in areas with a high proportion of desert-type vegetation, particularly in areas that differed in vegetation composition from nearby randomly sampled areas, than in areas with a high proportion of exotic or non-desert type vegetation. Associations between territorial behavior and habitat characteristics were not related to plasma T or CORT. Understanding the hormonal processes underlying these associations between behavior and habitat may provide insight into how free-ranging animals assess territorial quality and alter their defensive behavior accordingly. [Copyright &y& Elsevier]

We observed a change in the sex-specific rate of delayed natal dispersal in a stable population of Seychelles warblers over a period of 20 years. At first, females were more likely to delay dispersal in their first year of life than were males, whereas later there was no sex bias in the rate of delayed natal dispersal. Similarly, the female-bias in helping-at-the-nest and the male-bias in floating have also weakened over time. These changes may have resulted from the decrease in variation in territory quality observed in the population over the study period. Our findings strengthen the view that natal dispersal is a highly plastic response to local ecological and social circumstances, and clearly show that rates of sex-biased dispersal cannot be considered a species or population constant. Our study also highlights the importance of collecting long-term datasets to understand complex behaviour such as natal dispersal. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the associations between the vegetation structure of breeding territories, T-cell-mediated immune response, and body mass and plumage colour of Great Tits (Parus major). The study conducted the investigation with the use of a model of avian visual perception. Results of the study showed that plumage yellowness is related to plumage brightness and ultraviolet-blue reflectance, and mature vegetation which are also associated with immature habitats in territories. It mentions that there is a substantial variability in the growth of carotenoid-based colour elements under various environmental conditions. Conclusion suggests that the habitat quality is associated to immune response and nestling body mass through mechanisms variations.