Search

Capsule: Non-breeding Egyptian Vultures Neophron percnopterus tracked in Oman and the Horn of Africa ranged over large areas and made regular use of anthropogenic sources of food. Tracking data provide evidence that vultures monitor the availability of food within their home ranges. Aims: To study home range and movement patterns of non-breeding Egyptian Vultures. Methods: Five non-breeding Egyptian Vultures were tracked using Global Positioning System technology. Home range sizes were estimated using data only from vultures tracked for more than 11 months, and movements described. Analyses sought to determine whether patterns in movement were related to the location of rubbish dump sites and landfills. Results: Home range sizes of non-breeding Egyptian Vultures (95% kernel density estimator), ranged from 4238 to 7323 km². The average 3-hourly step length ranged from 3106.51 ± 173.16 m (mean ± se; median: 143.72 m; interquartile range, IQR: 2237.41 m) to 6519.46 ± 224.93 m (median: 2131.40 m; IQR: 7098.73 m). Egyptian Vulture activities centred on a few large rubbish dump sites that likely provided perpetually abundant food, but they frequently left those sites and visited other dumps. Conclusions: In line with what is known about Egyptian Vulture ecology, tracked birds ranged over large areas and made use of anthropogenic sources of food. Given the perpetual abundance of food at large rubbish dumps and in the presence of other scavengers feeding at them, there seemed little motivation for Egyptian Vultures to move away from them, unless it was to monitor food resources at other places within their home ranges. This movement behaviour likely reflects the potential benefit to vultures of knowledge about food availability in the wider environment, despite food being abundant at the site at which they are currently located. [ABSTRACT FROM AUTHOR]

Europe holds a rich community of diurnal birds of prey, and the highest proportion of transcontinental migratory raptorial species of any landmass. This study will test the hypotheses that the high diversification of the raptor assemblage in Europe is a recent event, that closely related species sharing the same trophic niches can only coexist in sympatry during the breeding period, when food availability is higher, and finally that migration is a function of size, with the smaller species in every trophic group moving further. A consensus molecular phylogeny for the 38 regular breeding species of raptors in Europe was obtained from BirdTree (www.birdtree.org). For the same species, a trophic niche cluster dendrogram was constructed. Size and migratory strategy were introduced in the resulting phylogeny, where trophic groups were also identified. Multispecific trophic groups tended to be composed of reciprocal sister species of different sizes, while monospecific groups ( n = 3) were composed of highly specialized species. Many speciation events took place recently, during the glacial cycles of the Quaternary, and size divergence among competing species may be due to character displacement. Nowadays, the smaller species in every trophic group migrate to sub-Saharan Africa. This investigation illustrates how the rich assemblage of diurnal birds of prey in Europe, more diverse and more migratory than, for instance, the North American assemblage at equivalent latitudes, has emerged recently due to the multiplication of look-alike species with similar trophic ecologies, possibly in climate refugia during cold periods., Competing Interests: The authors declare that they have no competing interests., (© 2022 Negro et al.)

Annual movements have been widely described for birds migrating across the Americas and between Eurasia and Africa, yet relatively little information exists for intra-African migrants. Identifying the areas used throughout a species annual cycle by understanding migratory patterns and settlement areas during breeding and non-breeding seasons is essential for conservation initiatives. Here, we describe for the first time, the migratory patterns and settlement areas of an endangered raptor endemic to Southern Africa, the Black Harrier (Circus maurus). From 2008 to 2015, thirteen breeding adult Black Harriers were trapped in south-western South Africa and fitted either with a GPS-GSM or with a PTT tracker device. Adults were monitored for 365 ± 198 days (range: 56-819 days) revealing great individual variability in annual movements. Most Black Harriers performed an unusual West-East migration from their breeding areas, but routes of all migrating individuals covered the entire southern land area of South Africa and Lesotho. The distance travelled averaged 814 ± 324 km, but unlike many other species, migrants travelled faster during post-breeding (i.e. austral summer) (207.8 ± 113.2 km.day-1) than during pre-breeding (i.e. austral winter/spring) migrations (143.8 ± 32.2 km.day-1). Although most marked individuals displayed movements similar to those that bred following pre-breeding migrations, only two of thirteen were confirmed as breeders the year after being tagged. This suggests that individuals may sometimes take a sabbatical year in reproduction, although this requires confirmation. Most tagged birds died on migration or during the non-breeding season. Adults frequently returned to the same non-breeding settlement areas, and often used up to 3 different locations an average of about 200 km apart. On the other hand, there was wide variation in distance between subsequent reproductive events. We discuss the implications of our study for the conservation of Black Harriers and more broadly for intra-African bird migrants., Competing Interests: The authors have declared that no competing interests exist.

Objective: Accurate measurement of fetal head biometry is important for fetal weight estimation (FWE) and is therefore an important prognostic parameter for neonatal morbidity and mortality and a valuable tool for determining the further obstetric management. Measurement of the head circumference (HC) in particular is employed in many commonly used weight equations. The aim of the present study was to find the most accurate method to measure head circumference for fetal weight estimation., Study Design: This prospective study included 481 term pregnancies. Inclusion criteria were a singleton pregnancy and ultrasound examination with complete fetal biometric parameters within 3 days of delivery, and an absence of structural or chromosomal malformations. Different methods were used for ultrasound measurement of the HC (ellipse-traced, ellipse-calculated, and circle-calculated). As a reference method, HC was also determined using a measuring tape immediately after birth. FWE was carried out with Hadlock formulas, including either HC or biparietal diameter (BPD), and differences were compared using percentage error (PE), absolute percentage error (APE), limits of agreement (LOA), and cumulative distribution., Results: The ellipse-traced method showed the best results for FWE among all of the ultrasound methods assessed. It had the lowest median APE and the narrowest LOA. With regard to the cumulative distribution, it included the largest number of cases at a discrepancy level of ±10%. The accuracy of BPD was similar to that of the ellipse-traced method when it was used instead of HC for weight estimation., Conclusion: Differences between the three techniques for calculating HC were small but significant. For clinical use, the ellipse-traced method should be recommended. However, when BPD is used instead of HC for FWE, the accuracy is similar to that of the ellipse-traced method. The BPD might therefore be a good alternative to head measurements in estimating fetal weight., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Variation is key to the adaptability of species and their ability to survive changes to the Earth's climate and habitats. Plasticity in movement strategies allows a species to better track spatial dynamics of habitat quality. We describe the mechanisms that shape the movement of a long-distance migrant bird (turkey vulture, Cathartes aura) across two continents using satellite tracking coupled with remote-sensing science. Using nearly 10 years of data from 24 satellite-tracked vultures in four distinct populations, we describe an enormous amount of variation in their movement patterns. We related vulture movement to environmental conditions and found important correlations explaining how far they need to move to find food (indexed by the Normalized Difference Vegetation Index) and how fast they can move based on the prevalence of thermals and temperature. We conclude that the extensive variability in the movement ecology of turkey vultures, facilitated by their energetically efficient thermal soaring, suggests that this species is likely to do well across periods of modest climate change. The large scale and sample sizes needed for such analysis in a widespread migrant emphasizes the need for integrated and collaborative efforts to obtain tracking data and for policies, tools and open datasets to encourage such collaborations and data sharing.

Background: Island faunas have played central roles in the development of evolutionary biology and ecology. Birds are among the most studied organisms on islands, in part because of their dispersal powers linked to migration. Even so, we lack of information about differences in the movement ecology of island versus mainland populations of birds., Methodology/principal Findings: Here we present a new general pattern indicating that large birds with deferred sexual maturity are sedentary on islands, and that they become so even when they are migratory on the mainland. Density-dependent variation in the age at first breeding affects the survivorship of insular populations and this, in turn, affects the movement ecology of large birds. Because density-dependent variation in the age of first breeding is critical to the long-term survival of small isolated populations of long-lived species, migratory forms can successfully colonize islands only if they become sedentary once there. Analyses of the movement ecology of continental and insular populations of 314 species of raptors, 113 species of Ciconiiformes and 136 species of passerines, along with individual-based population simulations confirm this prediction., Conclusions: This finding has several consequences for speciation, colonization and survival of small isolated population of species with deferred sexual maturity.

West Nile virus (WNV) has been identified in nearly 300 species of wild birds, including raptors, in North America since its introduction in New York City in 1999. American Kestrels (Falco sparverius) are susceptible to WNV infection, and the numbers of these birds have declined along the Atlantic coast in recent years. We examined the population biology and WNV exposure of kestrels breeding in the area surrounding Hawk Mountain Sanctuary in Kempton, Pennsylvania, USA. The reproductive biology of kestrels in this area was studied from 1992 until 2004. The number of kestrels breeding in nestboxes in 2004 was only 44% of the 6-yr mean observed prior to 1999. During the 2004 nesting season (study period: 8 June through 22 July 2004), adult kestrels were trapped near the site of their nestboxes. Blood samples were obtained, and serum antibodies specific to WNV were quantified using a plaque reduction neutralization test. Of 22 birds tested, 21 exhibited serum antibodies to WNV, suggesting that most (95%) of the adult kestrels in the population had been exposed to WNV.