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The left and right hippocampal formation (HF) of the avian brain have been reported to control some different aspects of homing in pigeons. In the current study, we employed GPS-tracking technology and unilateral HF lesions to further explore what if any aspects of a pigeon's homing flight might be under dominant control by either the left or right HF. Pigeons were released from three locations prior to any experimental manipulation and released repeatedly from the same three sites as sham-lesioned control, right HF-lesioned and left HF-lesioned treatment groups. Analyses of homing performance and virtual vanishing bearings revealed no effect of either lesion treatment. A more in-depth analysis of path efficiency during the initial decision-making, en route and near home phases of a homing flight also revealed no effect of either lesion treatment. A last analysis on the learning and memory for positions along a previously flown route, a proxy for investigating the development of route fidelity, also revealed no effect of either unilateral lesion. However, independent of treatment group, some statistically significant effects were observed with respect to changes in performance across training and the different release sites. The current study revealed no detectable difference between the left and right HF-lesioned pigeons with respect to several navigational parameters of a homing flight. Although in need of supporting experimentation, the results are consistent with the hypothesis that both the left and right HF are similarly able to support several aspects of homing pigeon navigation. No effect of unilateral HF-lesions on pigeons' homing was found. Both the left and right HF support local navigation and route fidelity development. [ABSTRACT FROM AUTHOR]

Seabirds are compelled to nest on land, away from their feeding areas, which they can only reach by leaving eggs or chicks in the nest, often for long periods of time. For this reason, almost all of them have evolved social monogamy as a reproductive system, cooperation between partners for incubation and chick rearing, and long-lasting pair bonds. Additionally, nesting conditions are essential for successful reproduction, and the nest can be considered a resource if it provides more guarantees in this aspect. As a result, the nest may be a source of contention and intraspecific competition, especially among males. In this work, we analyze long-term data of the Scopoli's shearwater (Calonectris diomedea) population to address the fitness consequences of nest change regarding survival and reproductive success. We used capture–recapture multistate models and the AICc model selection approach to test three hypotheses: breeding failure triggers nest change; nest change affects breeding success probability; nest change affects survival. Each year, about 5% of the breeders move to a new nest. For males, it was mainly a way to improve their breeding conditions and was observed in their early years as a breeder. Conversely, for females, it was a way to improve their reproductive performance by trying with a new mate after a failure. Males that changed nests improved their breeding success probability. Instead, in females, there was no causal relation between nest change and breeding success, the latter having been more influenced by the intrinsic quality of the female as a breeder. We did not even find a link between nest change and survival. Instead, we demonstrated that reproductive failure could affect the apparent survival of females, probably because it induces breeding dispersal. [ABSTRACT FROM AUTHOR]

Pelagic seabirds are tied to their breeding colonies throughout their long‐lasting breeding season, but at the same time, they have to feed in a highly dynamic marine environment where prey abundance and availability rapidly change across space and seasons. Here, we describe the foraging movements of yelkouan shearwater Puffinus yelkouan, a seabird endemic to the Mediterranean Sea that spends its entire life cycle within this enclosed basin and whose future conservation is intimately linked to human‐driven and climatic changes affecting the sea. The aim was to understand the main factors underlying the choice of foraging locations during the reproductive phases. A total of 34 foraging trips were obtained from 21 breeding adults tagged and tracked on Tavolara Archipelago (N Sardinia, Italy). This is the largest and most important breeding area for the species, accounting for more than 50% of the world population. The relationships between foraging movements during two different breeding stages and the seasonal changes of primary productivity at sea were modeled. Movements appeared to be addressed toward inshore (<20 km), highly productive, and relatively shallow (<200 m) foraging areas, often in front of river mouths and at great distances from the colony. During incubation, the Bonifacio Strait and other coastal areas close to North and West Sardinia were the most preferred locations (up to 247 km from the colony). During the chick‐rearing phase, some individuals reached areas placed at greater distances from the colony (up to 579 km), aiming at food‐rich hotspots placed as far north as the Gulf of Lion (France). The need for such long distance and long‐lasting foraging trips is hypothesized to be related to unfavorable conditions on the less productive (and already depleted) Sardinian waters. [ABSTRACT FROM AUTHOR]

The role of environmental olfactory information in pigeon navigation has been extensively studied by analysing vanishing bearing distributions and homing performances of homing pigeons subjected to manipulation of their olfactory perception and/or the olfactory information they were exposed to during transportation and at the release site. However, their behaviour during the homing flight remains undocumented. In this experiment we report the analysis of tracks of birds made anosmic at the release site by washing their olfactory mucosa with zinc sulfate. We thus can assess the role of local odours at the release site as well as the role of environmental odours perceived on the way, far from the release site. We observed that pigeons transported and kept at the release site in purified air and made anosmic at the release site were unable to orient towards home and were impaired at homing. By contrast, pigeons allowed to smell environmental odours during transportation and at the release site, although made anosmic prior to release, displayed unimpaired homeward orientation, but nevertheless showed impaired homing performance. These results are consistent with the view that local odours at the release site are critical for determining the direction of displacement (olfactory map) and suggest that pigeons consult the olfactory map also during their homing flight in order to be able to find their way home. [ABSTRACT FROM AUTHOR]

The Eurasian Stone-curlew is a species of conservation concern in Europe. We investigate for the first time the extent of population structure among populations sampled from six geographical areas, representing four subspecies inhabiting the western part of the species' distribution. Neither mitochondrial nor nuclear markers fully supported current subspecies boundaries. However, both markers support significant differentiation of the Canary Island populations from those sampled from the Mediterranean. Further work is needed to establish the taxonomic status of this potentially distinct Macaronesian taxon. More broadly, further genetic research is required to design and implement an effective conservation plan for this species. [ABSTRACT FROM AUTHOR]

\nHighlightsStudying pigeons during homing has offered an opportunity to investigate visual–functional brain lateralization in the context of free flying and long distance navigation. In the current study we examine at a high scale of spatial resolution the flight paths of pigeons, which vary with respect to monocular and binocular treatment, as they familiarise themselves with landscape and landmark features during repeated flights home from two locations. The analysis of the flight paths of monocularly occluded pigeons revealed that pigeons using the right eye/left hemisphere visual system were more likely to display more tortuous paths over tracts of 500 m along the flight path home compared to both pigeons using the left eye/right hemisphere visual system and control birds. Accompanying this finding was the observation that pigeons using the right eye/left hemisphere system were more likely to perform flight “loops”, suggesting that, without right hemispheric visual processing, pigeons are more motivated to seek out visual input, behaviourally expanding the now monocularly reduced visual field. Taken together, the data are consistent with a more important role of the left eye/right hemisphere system in processing visual features of the landscape, which may contribute to the construction of the familiar landmark-based map used for navigation. More broadly, our data are consistent with the hypothesis that the right cerebral hemisphere of the avian brain plays a more important role in memorising and using the relational properties of visual stimuli to guide performance on spatial tasks. Pigeons challenged to learn visual landscape features with only the left or right eye displayed different patterns of flight behaviour.Birds using the right eye/left hemisphere showed a greater high spatial resolution tortuosity than birds using the left eye/right hemisphere.The results are consistent with an important role of the avian right brain hemisphere in memory-based, visuo-spatial tasks.Pigeons challenged to learn visual landscape features with only the left or right eye displayed different patterns of flight behaviour.Birds using the right eye/left hemisphere showed a greater high spatial resolution tortuosity than birds using the left eye/right hemisphere.The results are consistent with an important role of the avian right brain hemisphere in memory-based, visuo-spatial tasks. [ABSTRACT FROM AUTHOR]