scholarly journals Influence of age and sex on winter site fidelity of sanderlingsCalidris alba

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2517 ◽  
Author(s):  
Pedro M. Lourenço ◽  
José A. Alves ◽  
Jeroen Reneerkens ◽  
AH Jelle Loonstra ◽  
Peter M. Potts ◽  
...  

Many migratory bird species show high levels of site fidelity to their wintering sites, which confers advantages due to prior knowledge, but may also limit the ability of the individual to move away from degrading sites or to detect alternative foraging opportunities. Winter site fidelity often varies among age groups, but sexual differences have seldom been recorded in birds. We studied a population of individually colour-marked sanderlings wintering in and around the Tejo estuary, a large estuarine wetland on the western coast of Portugal. For 160 individuals, sighted a total of 1,249 times between November 2009 and March 2013, we calculated the probability that they moved among five distinct wintering sites and how this probability is affected by distance between them. To compare site fidelity among age classes and sexes, as well as within the same winter and over multiple winters, we used a Site Fidelity Index (SFI). Birds were sexed using a discriminant function based on biometrics of a large set of molecularly sexed sanderlings (n= 990). The vast majority of birds were observed at one site only, and the probability of the few detected movements between sites was negatively correlated with the distance among each pair of sites. Hardly any movements were recorded over more than 15 km, suggesting small home ranges. SFI values indicated that juveniles were less site-faithful than adults which may reflect the accumulated knowledge and/or dominance of older animals. Among adults, females were significantly less site faithful than males. A sexual difference in winter site fidelity is unusual in shorebirds. SFI values show site-faithfulness is lower when multiple winters were considered, and most birds seem to chose a wintering site early in the season and use that site throughout the winter. Sanderlings show a very limited tendency to explore alternative wintering options, which might have implications for their survival when facing habitat change or loss (e.g., like severe beach erosion as can be the case at one of the study sites).

2007 ◽  
Vol 13 (2) ◽  
pp. 111 ◽  
Author(s):  
Debbie Saunders ◽  
Raymond Brereton ◽  
Chris Tzaros ◽  
Mark Holdsworth ◽  
Rob Price

Conserving habitat for wide-ranging fauna species provides a challenge because impacts on these species tend to be dismissed based on the assumption that there is sufficient habitat in other areas of its range. This incremental loss of habitat is a serious conservation issue for a diversity of bird species. As knowledge of wide-ranging and migratory bird species increases, it often becomes evident that they select specific sites on a regular basis (i.e., the species exhibit site fidelity). Gaining a better understanding of site fidelity and selective habitat use for wide-ranging species is clearly important, but also extremely challenging. In this paper, challenges associated with conservation of the migratory and wide-ranging Swift Parrot Lathamus discolor are discussed as an example of how a recovery programme has aimed to address such conservation and management challenges. Despite the small population size (less than 2 500 birds), broad distribution (1 250 000 km2) and often cryptic nature, the implementation of the national recovery programme has been successful in the identification and protection of important habitats. This has been made possible by involving large numbers of volunteers who collect long-term sighting and habitat data over large areas, together with more detailed ecological research. This information is then used to inform the conservation assessment process and to improve habitat conservation throughout the range of the species.


2008 ◽  
Vol 24 (3) ◽  
pp. 291-299 ◽  
Author(s):  
Miriam M. Hansbauer ◽  
Ilse Storch ◽  
Rafael G. Pimentel ◽  
Jean Paul Metzger

Abstract:In this paper, we report on range use patterns of birds in relation to tropical forest fragmentation. Between 2003 and 2005, three understorey passerine species were radio-tracked in five locations of a fragmented and in two locations of a contiguous forest landscape on the Atlantic Plateau of São Paulo in south-eastern Brazil. Standardized ten-day home ranges of 55 individuals were used to determine influences of landscape pattern, season, species, sex and age. In addition, total observed home ranges of 76 individuals were reported as minimum measures of spatial requirements of the species. Further, seasonal home ranges of recaptured individuals were compared to examine site fidelity.Chiroxiphia caudata, but notPyriglena leucopteraorSclerurus scansor, used home ranges more than twice as large in the fragmented versus contiguous forest. Home range sizes ofC. caudatadiffered in relation to sex, age, breeding status and season. Seasonal home ranges greatly overlapped in bothC. caudataand inS. scansor. Our results suggest that one response by some forest bird species to habitat fragmentation entails enlarging their home ranges to include several habitat fragments, whereas more habitat-sensitive species remain restricted to larger forest patches.


2015 ◽  
Vol 32 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Jan Christian Habel ◽  
Jessica Hillen ◽  
Thomas Schmitt ◽  
Christina Fischer

Abstract:Species with specific habitat requirements often remain within their habitat and are characterized by a very sedentary behaviour. We used radio-tracking during a 3-wk campaign to investigate the home ranges and movements of three East African passerine bird species, all adapted to cloud-forest habitats: montane white-eye Zosterops poliogaster mbuluensis, stripe-cheeked greenbul Andropadus milanjensis and white-starred robin Pogonocichla stellata macarthuri. Individuals were observed in a forest-grassland mosaic on top of Chyulu Hills, south Kenya. Based on 15 individuals with a total of 1041 fixes, we found (1) that all three species show a sedentary behaviour restricted to their home forest patch; (2) least activity during the afternoon; and (3) re-colonization into its home patch after translocation into a nearby forest patch. Our findings underline that forest-specialist bird species of the tropics show high site fidelity despite their potential movement ability.


2021 ◽  
Vol 75 (11) ◽  
Author(s):  
Yvonne R. Schumm ◽  
Benjamin Metzger ◽  
Eric Neuling ◽  
Martin Austad ◽  
Nicholas Galea ◽  
...  

Abstract Populations of migratory bird species have suffered a sustained and severe decline for several decades. Contrary to non-migratory species, understanding the causal mechanisms proves difficult (for migratory bird species) as underlying processes may operate across broad geographic ranges and stages of the annual cycle. Therefore, the identification of migration routes, wintering grounds, and stopover sites is crucial for the development of relevant conservation strategies for declining migrant bird species. We still lack fundamental data of the non-breeding movements for many migratory species, such as European turtle doves Streptopelia turtur, a trans-Saharan migrant. For this species, knowledge of non-breeding movements is mainly based on ringing data that are limited by a low recovery rate in Africa, and tracking studies with a strong bias towards individuals breeding in France. We used Argos satellite transmitters to obtain detailed year-round tracks and provide new insights on migration strategies and winter quarters, of turtle doves breeding in Central and Eastern Europe. The tracking data along with analysis of land cover data confirm previously assumed use of multiple wintering sites and the use of a wide range of forest and agricultural landscapes at the breeding grounds. Tracking data in combination with environmental parameters demonstrated that most environmental parameters and niche breadth differed between breeding and wintering grounds. “Niche tracking” was only observed regarding night-time temperatures. Furthermore, we provide evidence for breeding site fidelity of adult individuals and for home range size to increase with an increasing proportion of agricultural used areas. Significance statement The European turtle dove, a Palearctic-African migrant species, is one of the fastest declining birds in Europe. The rapid decline is presumed to be caused mainly by habitat modification and agricultural changes. Here, we represent data on migration strategies, flyways, and behavior on European breeding and African non-breeding sites of turtle doves breeding in Central and Eastern Europe equipped with satellite transmitters. Our results confirm the use of different migration flyways and reveal an indication for “niche switching” behavior in terms of environmental factors during the different annual phases. The migratory behaviors revealed by the tracking approach, e.g., prolonged stopovers during autumn migration in Europe overlapping with time of hunting activities, stopovers in North Africa during spring migration, or evidence for loop migration, are important protection-relevant findings, particularly for the Central-Eastern flyway, for which no tracking data has been analyzed prior to our study.


2018 ◽  
Vol 96 (8) ◽  
pp. 869-875 ◽  
Author(s):  
J.W. Ng ◽  
E.C. Knight ◽  
A.L. Scarpignato ◽  
A.-L. Harrison ◽  
E.M. Bayne ◽  
...  

Over one third of North American bird species are in decline, and for many species, we still lack fundamental biogeographic information such as migration routes and nonbreeding areas. Identifying causes of declines is limited because tracking many species throughout their annual cycle with high precision and accuracy is challenging. Common Nighthawks (Chordeiles minor (J.R. Forster, 1771)) have declined throughout much of their range and have yet to have their migratory and nonbreeding areas identified and characterized. We tracked Common Nighthawks by deploying a new 3.5 g Pinpoint GPS-Argos tag on adult males. Seven of 10 (70%) tags uploaded locations, providing the first data on migration, nonbreeding habitat, and annual site fidelity to breeding areas. Birds used similar loop migration routes and overwintered in Brazil’s Cerrado and Amazon regions. Nonbreeding season roosting home ranges were 148.22 ± 121 ha (mean ± SE) and included forest, grassland, and cropland. Breeding home-range fidelity was high; all tracked birds returned to within 1.27 ± 0.27 km of original capture locations. Our study is the first tracking of Common Nighthawks throughout their full annual cycle. Continued miniaturization of tracking technology, like the GPS-Argos transmitters used, is critical for identifying the causes of population declines of previously enigmatic migratory species.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malin Indremo ◽  
Richard White ◽  
Thomas Frisell ◽  
Sven Cnattingius ◽  
Alkistis Skalkidou ◽  
...  

AbstractThe aim of this study was to examine the validity of the Gender Dysphoria (GD) diagnoses in the Swedish National Patient Register (NPR), to discuss different register-based definitions of GD and to investigate incidence trends. We collected data on all individuals with registered GD diagnoses between 2001 and 2016 as well as data on the coverage in the NPR. We regarded gender confirming medical intervention (GCMI) as one proxy for a clinically valid diagnosis and calculated the positive predictive value (PPV) for receiving GCMI for increasing number of registered GD diagnoses. We assessed crude and coverage-adjusted time trends of GD during 2004–2015 with a Poisson regression, using assigned sex and age as interaction terms. The PPV for receiving GCMI was 68% for ≥ 1 and 79% for ≥ 4 GD-diagnoses. The incidence of GD was on average 35% higher with the definition of ≥ 1 compared to the definition of ≥ 4 diagnoses. The incidence of GD, defined as ≥ 4 diagnoses increased significantly during the study period and mostly in the age categories 10–17 and 18–30 years, even after adjusting for register coverage. We concluded that the validity of a single ICD code denoting clinical GD in the Swedish NPR can be questioned. For future research, we propose to carefully weight the advantages and disadvantages of different register-based definitions according to the individual study’s needs, the time periods involved and the age-groups under study.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Acácio ◽  
Ralf H. E. Mullers ◽  
Aldina M. A. Franco ◽  
Frank J. Willems ◽  
Arjun Amar

AbstractAnimal movement is mainly determined by spatial and temporal changes in resource availability. For wetland specialists, the seasonal availability of surface water may be a major determinant of their movement patterns. This study is the first to examine the movements of Shoebills (Balaeniceps rex), an iconic and vulnerable bird species. Using GPS transmitters deployed on six immature and one adult Shoebills over a 5-year period, during which four immatures matured into adults, we analyse their home ranges and distances moved in the Bangweulu Wetlands, Zambia. We relate their movements at the start of the rainy season (October to December) to changes in Normalized Difference Water Index (NDWI), a proxy for surface water. We show that Shoebills stay in the Bangweulu Wetlands all year round, moving less than 3 km per day on 81% of days. However, average annual home ranges were large, with high individual variability, but were similar between age classes. Immature and adult Shoebills responded differently to changes in surface water; sites that adults abandoned became drier, while sites abandoned by immatures became wetter. However, there were no differences in NDWI of areas used by Shoebills before abandonment and newly selected sites, suggesting that Shoebills select areas with similar surface water. We hypothesise that the different responses to changes in surface water by immature and adult Shoebills are related to age-specific optimal foraging conditions and fishing techniques. Our study highlights the need to understand the movements of Shoebills throughout their life cycle to design successful conservation actions for this emblematic, yet poorly known, species.


2014 ◽  
Vol 143 (8) ◽  
pp. 1681-1691 ◽  
Author(s):  
M. E. ARNOLD ◽  
R. J. GOSLING ◽  
F. MARTELLI ◽  
D. MUELLER-DOBLIES ◽  
R. H. DAVIES

SUMMARYThere has been a rapid rise in the prevalence of cases of monophasic Salmonella Typhimurium (mST) in both humans and farm animals, and it has been found in pigs, cattle and poultry. It is therefore vital to have a good understanding of how to efficiently detect infected farms. The objective of this project was to determine sample type sensitivity in the detection of Salmonella to detect infected groups of animals on both pig (breeder, grower and finisher sites) and cattle (beef and dairy) farms, using data collected from a study investigating farms that were positive for mST, and to explore any variation between different age groups and management practices. A Bayesian approach in the absence of a gold standard was adopted to analyse the individual and pooled faecal sample data collected from each epidemiological group on each of the farms. The sensitivity of pooled sampling depended on the prevalence of infection in the group being sampled, with a higher prevalence leading to higher sensitivity. Pooled sampling was found to be more efficient at detecting positive groups of animals than individual sampling, with the probability of a random sample from a group of animals with 5% prevalence testing positive being equal to 15·5% for immature pigs (3·6% for an individual faecal sample, taking into account the sensitivity and infection prevalence), 7·1% for adult pigs (1·2% for individual sampling), 30% for outdoor cattle (2% for individual sampling) and 34% for indoor cattle (1% for individual sampling). The mean prevalence of each epidemiological group was higher in outdoor farms than indoor for both pigs and cattle (mean within-farm prevalence of 29·4% and 38·7% for outdoor pigs and cattle, respectively, compared to 19·8% and 22·1% for indoor pigs and cattle)


Behaviour ◽  
2013 ◽  
Vol 150 (14) ◽  
pp. 1689-1708 ◽  
Author(s):  
A.J.W. Ward ◽  
R. James ◽  
A.D.M. Wilson ◽  
M.M. Webster

The ability of animals to disperse towards their original home range following displacement has been demonstrated in a number of species. However, little is known about the homing ability of three-spine sticklebacks (Gasterosteus aculeatus), an important model species in behavioural ecology. In addition, few studies have examined the role of social facilitation in relation to homing behaviour in fishes. We examined homing behaviour of sticklebacks displaced over distances of between 80 m and 160 m in land-drains with directional water flow. Fish were translocated from their original capture site, tagged and then released either in groups or solitarily. We performed recapture transects either one or two days later. Data provided by recaptured sticklebacks show that the fish dispersed in the direction of their original capture site. Although fish translocated downstream typically moved further than those translocated upstream, both dispersed towards their original capture site. There was no difference between fish released solitarily or in groups in their homing ability and indeed there was little evidence that fish translocated in groups remained together following their release. The homing ability of the fish was demonstrated by the finding that up to 80% of fish returned to their home ranges within two days of release over a distance equivalent to approximately 5000 body lengths of these small fish.


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