Segregation in the African wintering ranges of English and Swiss Swallow Hirundo rustica populations: a stable isotope study

Capsule Stable isotope analysis of Swallow feathers, grown in Africa, revealed significant differences between populations breeding in Switzerland and England.

Aims To investigate the extent to which Swallow populations breeding in Switzerland and England are separated on their African wintering grounds.

Methods Swallows were caught at breeding colonies, biometric measurements were taken and feathers, grown in Africa, were collected. Feathers were combusted in a Carlo Erba C/N/S analyser and the δ¹³C and δ¹⁵N signatures were measured using a mass spectrometer.

Results The δ¹³C signatures of Swiss birds were significantly more depleted than those of birds from England. The δ¹⁵N signatures did not differ between the two populations.

Conclusion Birds from Switzerland and England probably winter in geographically distinct parts of Africa. The Swiss birds probably feed on prey that are more reliant on C₃ vegetation, from woodlands, than the prey of English birds, which are more reliant on C₄ vegetation, from grasslands.     

Breeding ecology of the Eastern Great Reed Warbler Acrocephalus arundinaceus orientalis at Lake Kasumigaura,central Japan

CapsuleTwo populations of the Eastern Great Reed Warblers, one close to settlements and one far away, differed mainly in nest losses which were higher at the latter site.

Aims To compare the breeding ecology of two Japanese populations, and with breeding data from Polish sites.

Methods We studied two sites in 1996. The Seimei site comprises a natural reed-bed (Phragmites australis) (2.0 ha) c. 2 km from residential areas. The Sakura site occurs as smaller reed-bed (0.8 ha) close to residential areas. Field study comprised mainly nest searching and nest monitoring.

Results Breeding density, nest height, number of stems supporting nest, clutch size and brood size were not significantly different between sites. The proportion of nests built on reed stems standing in the water (60%) was significantly higher at the Seimei site (P < 0.001), and the warblers in this habitat experienced significantly higher nesting failure (P < 0.05). Predation was a principal cause of failure at both sites. Significantly more nests suffered from predation at Seimei (53%) than at Sakura (16%). Breeding density was higher at both sites compared with European populations but it fell within ranges of other Japanese populations. Mean first-egg date of first brood does not differ between our sites and Polish ones.

Conclusion The differences between the two Japanese populations and between Japanese and Polish populations were relatively small and were seen mainly in nest losses, breeding density and proportion of nests built over water.     

Few genetic differences between Victorian and Western Australian blue penguins,Eudyptula minor

Abstract

Blue penguins, Eudyptula minor, breeding on Penguin Island, Western Australia are considerably larger than other blue penguins in Australia. If genetic isolation is the cause, it may have implications for the conservation status of some blue penguin populations. We compared the sequences of two mitochondrial gene regions (cytochrome‐b and the control region) from Western Australian blue penguins with other populations of blue penguins from Australia and New Zealand. We found few differences between sequences from Western Australia, Phillip Island, Victoria and Otago, New Zealand, although all three differed considerably from other New Zealand blue penguins. Sequences for the control region from the Western Australian blue penguins and 30 more birds breeding at various Australasian sites provided further support for two major clades within Eudyptula; an Australian clade (including Otago) and a New Zealand clade.     

The breeding population of Peregrine Falcon Falco peregrinus in the United Kingdom,Isle of Man and Channel Islands in 2014

Capsule: Overall numbers of Peregrines are higher than previously recorded, due primarily to the growth of lowland populations, despite declines in many upland areas.

Aims: To estimate the breeding population of Peregrines, and changes in this population over time, as well as to relate variation in trends and observed breeding success to variation in region, breeding site type and other ecological influences.

Methods: Two types of survey methods were used. Site-based visits focussed on locations where Peregrines were known to have bred previously, while area-based searches aimed to find all Peregrines breeding in randomly chosen 5?km?×?5?km squares. Findings from each method were used to estimate population size in different parts of the survey area. Breeding outcome and site type were assessed for most of the pairs found during either survey.

Results: In 2014, the breeding population of Peregrines in the UK, Isle of Man and Channel Islands was estimated at 1769 pairs. This is 22% larger than the population estimate from the previous survey in 2002. Most of this increase is accounted for by increases in lowland England. Populations in some upland areas have declined.

Conclusions: The gap between the fortunes of lowland and upland Peregrines has continued to grow, along with the overall UK population. Likely reasons for the continued success of Peregrines in the lowlands include increasing uptake of breeding sites on human structures, abundant availability of prey in many lowland situations and, in many areas, a relative lack of conflict with humans. Factors likely to be limiting upland Peregrine populations vary between different regions, and include ongoing illegal killing and deliberate disturbance, and food supply.     

Breeding status of the Red Kite Milvus milvus in Britain in 2000

Capsule The first co-ordinated Red Kite survey across Britain since the reintroduction programme began in 1989, yields 430 breeding pairs.

Aims To estimate the current size and extent of the British breeding population.

Methods A complete census of the populations in the East Midlands, Yorkshire, central and north Scotland was undertaken, while in Wales and the Chilterns, populations were surveyed using a stratified sample of tetrads. Breeding and territorial pairs were identified.

Results The survey indicated that there were 430 breeding pairs in Britain (95% CIs, 372–490). There were 259 breeding pairs in Wales (95% CIs, 200–318) and 109 (95% CIs, 96–124) in the Chilterns. Elsewhere, 16 breeding pairs were located in the East Midlands, three in Yorkshire, seven in central Scotland and 33 in north Scotland. An additional three pairs were recorded in southern England, away from the main population centres.

Conclusion The 2000 survey provides a baseline against which to measure future changes in Red Kite populations in Britain, using standard, repeatable methods.     

Circumpolar variation in morphological characteristics of Greater White-fronted Geese Anser albifrons

Capsule Greater White-fronted Geese show significant variation in body size from sampling locations throughout their circumpolar breeding range.

Aims To determine the degree of geographical variation in body size of Greater White-fronted Geese and identify factors contributing to any apparent patterns in variation.

Methods Structural measures of >3000 geese from 16 breeding areas throughout the Holarctic breeding range of the species were compared statistically.

Results Palearctic forms varied clinally, and increased in size from the smallest forms on the Kanin and Taimyr peninsulas in western Eurasia to the largest forms breeding in the Anadyr Lowlands of eastern Chukotka. Clinal variation was less apparent in the Nearctic, as both the smallest form in the Nearctic and the largest form overall (the Tule Goose) were from different breeding areas in Alaska. The Tule Goose was 25% larger than the smallest form. Birds from Greenland (A. a. flavirostris) were the second largest, although only slightly larger than geese from several North American populations. Body size was not correlated with breeding latitude but was positively correlated with temperature on the breeding grounds, breeding habitat, and migration distance. Body mass of Greater White-fronted Geese from all populations remained relatively constant during the period of wing moult. Morphological distinctness of eastern and western Palearctic forms concurs with earlier findings of complete range disjunction.

Conclusions Patterns of morphological variation in Greater White-fronted Geese across the Holarctic can be generally attributed to adaptation to variable breeding environments, migration requirements, and phylo-geographical histories.     

Distribution,endogamy, and isolation of Malas of Chittoor district,Andhra Pradesh,India

Abstract

In the present investigation, it is observed that there are at least six endogamous Mala populations namely, the Tangala, the Maladasari, the Pakanati, the Rampala, the Murikinati, and the Bommanati inhabiting the two taluks of Chittoor district of Andhra Pradesh. From the projected distribution of these populations, it is evident that the populations show a regionality in their distribution, without any overlapping even when two different populations inhabit the same village. It can also be inferred that the six Mala populations satisfy Wright's island model of breeding structure. These populations show low mean marriage distances. Within each there is some degree of breeding isolation by distance, and there is an approach to the neighborhood or, more aptly, the stepping stone model.     

Population estimates,trends and habitat associations of breeding Lapwing Vanellus vanellus,Curlew Numenius arquata and Snipe Gallinago gallinago in Northern Ireland in 1999

Capsule Declines in the breeding populations of Snipe, Lapwing and Curlew were recorded between April and June 1999 and compared with previous estimates in 1987.

Aims To compare populations of non-coastal breeding waders between 1987 and 1999.

Methods In 106 2 km × 2 km square tetrads, observers recorded the number of breeding pairs of waders and habitat details on 1:10 000 scale maps.

Results A significant decline of c. 60% for Lapwing and Curlew, and a non-significant decline of 30% for Snipe was recorded over 12 years. Concentrations of these species were found in County Tyrone, but Counties Antrim, Down and Armagh supported few breeding pairs of any species. Very few pairs of any species were recorded on improved grassland despite its widespread availability.

Conclusion A successful conservation strategy for these species must address the wider countryside and not just key sites. Intensive pastoral farming in upland and lowland areas and activities such as drainage and peat extraction will further reduce the suitability of open habitats for these wader species.     

Variations in Black Guillemot Cepphus grylle natal dispersal and philopatry across Britain and Ireland

Capsule: Using ring recovery records collected in Britain and Ireland from 1935 to 2015, we investigated philopatry and dispersal in Black Guillemots Cepphus grylle ringed as nestlings and recovered at breeding age during the breeding season. Levels of philopatry and dispersal distance varied between colonies, and were significantly related to latitude, possibly due to differences in ecology between populations. However, an increase in ringing effort is required to allow robust comparisons of these behaviours between colonies.     

Infestations of Ornithonyssus bursa,a haemotophagous mite,on starlings over the non-breeding season

Abstract

Ornithonyssus bursa (Berlese) (Dermanyssidae) is found in nests and neotboxes and on nestlings of the starling (Sturnus vulgaris L.), sometimes in large numbers, during the breeding season. During the non-breeding season the nestboxes and nest material are devoid of live mites. O. bursa overwinters ectoparasitically on starlings, and is present on approximately 25% of the population at the beginning of the breeding season. These nucleus populations build up rapidly in nest boxes during the breeding season.     

Effects of consecutive,contrasting, winters on the bird population of an Anglesey pine plantation

Capsule European Nightjars Caprimulgus europaeus breeding in southern England were found to over-winter in the Democratic Republic of Congo.

Aims To ascertain the wintering areas and migration routes of European Nightjars breeding in southern England.

Methods The wintering areas of three Nightjars were mapped using light geolocation tags (two in 2008 and one in 2010). For one of these birds, details of the timing and route of migration were determined. The impact of the birds' behaviour on location accuracy was measured and data on the timing of emergence and roosting was collected.

Results All three Nightjars were found to be wintering in the south and east of the Democratic Republic of Congo, in an area not previously considered to be part of the wintering range of this species. The route of migration differed in each period. Autumn migration was across central Sahara, whereas in spring the route was to the west of the Sahara. Aberrations in the light curve caused by the roosting and emergence of the birds were found to affect the estimated location of the wintering areas, shifting them approximately 1° south, and reducing the estimated accuracy of the locations. The timing of these aberrations showed that roosting and emergence roughly follow the timing of dawn and dusk.

Conclusions Current distribution maps for the wintering areas of Nightjars in Africa probably under-represent the true distribution of the species in the continent. The wide dispersal of birds from the same breeding area in the UK may be an indication of mixing of breeding populations during the wintering period. Further study is needed to understand how these results fit into the larger picture of Nightjar migration both from the UK and the wider Eurasian breeding range, and to determine locations of stopovers.     

Breeding biology of the endangered Dupont’s Lark Chersophilus duponti in two separate Spanish shrub-steppes

Capsule: The Dupont’s Lark Chersophilus duponti in Iberia has relatively high breeding success in both core and fragmented habitats, so population declines are more likely to be the result of low juvenile or adult survival.

Aims: To measure important aspects of the reproductive biology of one of the most endangered and least known larks: the Dupont’s Lark C. duponti.

Methods: We monitored 36 nests in 2 Spanish shrub-steppes, one holding one of the largest European populations (250 pairs) and one composed by fragmented habitat patches holding a smaller population (50 pairs).

Results: The breeding season went from late-March to early July. Overall mean (±sd) clutch size was 3.47?±?0.56, and the number of fledglings per successful nest was 3.0?±?1.15. Mean nestling period was short (8.2 days). Nests showed similar daily survival rate during the incubation period (0.9750?±?0.0110) as during the nestling period (0.9545?±?0.0168), with a mean breeding success of 50%. Predation was the main cause of complete nest failure (83.3% of failed nests in both localities).

Conclusion: Breeding parameters did show no significant variation between populations. Breeding success in both sites was generally higher than recorded in previous studies of this and most other lark species, which suggests that breeding success does not compromise long-term viability of these populations. The decline of the studied populations should be explained by other causes, such as a general decrease in habitat quality, habitat loss or habitat fragmentation.     

Hunting and the fate of French breeding waterbirds

Capsule French breeding populations of hunted waterbirds have more negative long-term population trends than closely related non-hunted species.

Aims To assess the relative fate of breeding populations of hunted and non-hunted waterbird species in France.

Methods We compared long-term population growth rates of hunted versus non-hunted waterbirds using two large-scale and long-term national surveys.

Results Waterbirds globally displayed long-term increases in population sizes most likely driven by their positive response to the implementation of numerous protected areas over remnant wetlands across the country since the early 1970s. In contrast, hunted species revealed more negative trends compared to non-hunted species.

Conclusion A causal relationship between hunting and population dynamics is not demonstrated here, but the results are consistent with species' breeding populations being negatively affected, on average, if they are hunted.     

Breeding ecology of Kentish Plover Charadrius alexandrinus in an extremely hot environment

Capsule Hot environments are associated with more biparental care, high nest‐site fidelity and low mate fidelity.

Aims To investigate the breeding ecology and parental behaviour of Kentish Plovers in an extremely hot environment. Kentish Plovers have an unusually diverse breeding system in which the frequencies of biparental, female‐only and male‐only care vary between populations. A common, but rarely tested, explanation for such a variation is local adaptation: birds exhibit social traits that are adaptive to their breeding environment. In particular, we investigated the effect of a hot environment on breeding success, distribution of care types, and mate and site fidelity.

Methods A breeding population of approximately 200 pairs of Kentish Plovers was investigated in 2005 and 2006 at Al Wathba Wetland near Abu Dhabi in the United Arab Emirates.

Results We found high nest‐site fidelity, low mate fidelity and more biparental care in Al Wathba than in most temperate zone populations of Kentish Plovers.

Conclusions Our results are consistent with the argument that a harsh environment can select for biparental care. However, further studies are warranted to distinguish between alternative hypotheses for the different distribution of social behaviours of breeding populations.     

Sediment destabilizing and stabilizing bio-engineers on tidal flats: cascading effects of experimental exclusion

Bioturbating lugworms (Arenicola marina) were excluded from 400 m2 plots of intertidal sand which initiated sequences of direct and indirect changes in the structure of the benthic community. The sessile, tube-building species Polydora cornuta and Lanice conchilega took advantage of the absence of lugworms and settled preferentially on lugworm exclusion plots. The protruding tubes provided attachment for an ephemeral development of algal tufts (Berkeleya colonies and Enteromorpha thalli) which in turn enhanced settlement of the juvenile drifting clams Mya arenaria and Macoma balthica. This causal chain of enhanced bivalve settlement in the presence of above-ground structures, like animal tubes and algae, on lugworm exclusion plots occurred in 2 years at different tidal zones with different tube builders, algae and juvenile clams. A significant response of L. conchilega in a year with relatively low lugworm abundances at the entire site suggests that not only the actual absence of large bioturbators was responsible for the establishment of tube-dwelling species, but also a cumulative change of the sediment in exclusion plots since the onset of the experiment. While the sediment on lugworm plots remained permeable, fine particles and organic matter accumulated at exclusion plots. It is suggested that these differences in sediment characteristics were the product of divergent benthic engineering by sediment destabilizing lugworms on control plots and sediment stabilizing species on exclusion plots. Cumulative changes of the sedimentary habitat and cascading effects in the benthic community may explain the persistence of patches that are dominated by either sediment stabilizing or destabilizing species in the assemblage mosaic of intertidal sediments.     

Supernumerary chromosomes of the harvest mouse,Reithrodontomys megalotis

Chromosomes were analyzed from 282 field captured and 76 laboratory specimens of the Western Harvest Mouse, Reithrodontomys megalotis. The supernumerary chromosomes found in this species varied from 0 to 7 causing a variation in diploid number of from 42 to 49 with the modal class being 2n=44. The relative frequency of various numbers varied between populations, which were taken from Arizona, California, Nebraska, New Mexico and Utah. Laboratory breeding experiments and cytological evidence indicate differences in the rate of non-disjunction is responsible for interpopulational variation. A hypothesis is suggested to explain this variation as it relates to the evolution and zoogeography of the species.     

Recent changes in the abundance of British upland breeding birds

Capsule Breeding wader populations have more often shown declines than passerine populations during the last 10–20 years.

Aims To determine abundance changes in British upland breeding birds during the last 10–20 years.

Methods We re-surveyed 1348 km², in nine study areas, of the British uplands in 2000 and 2002, which had been previously surveyed between 1980 and 1991. In addition, we included data from recent repeat surveys in four other upland areas, covering approximately 365 km², to broaden the scope of our study.

Results We found evidence of widespread population declines in three species of breeding waders, Lapwing Vanellus vanellus, Dunlin Calidris alpina and Curlew Numenius arquata. Among the passerines, some species declined, including Twite Carduelis flavirostris and Ring Ouzel Turdus torquatus, while others showed strong gains, including Stonechat Saxicola torquata and Raven Corvus corax.

Conclusion Overall, abundance changes were characterized by a high degree of variability across study areas, even when close together. This variability may have been partly due to the different time intervals between the original and repeat surveys. Improved upland breeding bird population monitoring is needed to allow better detection of trends. Action is needed to restore upland breeding bird populations in areas where they have declined.     

Population trend and breeding biology of Montagu's Harrier Circus pygargus in a natural vegetation site in northeast Spain

Capsule Reproductive output in a natural habitat was higher than in birds breeding in cereal crops, highlighting the importance of natural habitats for the species.

Aims To evaluate breeding in a natural habitat in inland Castellon province, Spain, and compare breeding parameters with other European populations.

Methods Breeding population size in inland Castellon was recorded between 1981 and 2003. A logistic growth model was used to describe population increase. We also calculated clutch size, brood size, productivity, percentage of successful nests and fledging success for the period 1989–2003.

Results Population size increased from three pairs in 1981 to 98 pairs in 2003. During 1989–2003, productivity (2.74 ± 1.49 fledglings/pair) and percentage of successful nests (84.%) were higher than observed in other European populations.

Conclusions Our results show the importance of our study area for the conservation of this species in the Iberian Peninsula, as it might act as a source of colonists for other areas. Food and protection against predators might explain the high breeding output, which may in turn explain the rapid population growth in the area. The study also suggests that natural habitats might be important for the species elsewhere.     

Status of the Hen Harrier Circus cyaneus in the UK and Isle of Man in 2004, and a comparison with the 1988/89 and 1998 surveys

Capsule The population of breeding Hen Harriers in the UK and Isle of Man increased between 1998 and 2004, although country and regional trends differed.

Aims To estimate the size of the UK and Isle of Man Hen Harrier breeding population in 2004, and to compare this with previous estimates made in 1988/89 and 1998.

Methods Surveys were carried out in core and a stratified random sample of 10-km squares throughout the known range, using the same methods as in the 1988/89 and 1998 national surveys.

Results There were an estimated 806 territorial pairs in the UK and Isle of Man in 2004, a significant 41% increase from the 1998 estimate of 570 pairs. Increases were found throughout, with the exception of south and east Scotland and England, where numbers decreased. Scotland held 79% of the UK and Isle of Man breeding population in 2004, and 10% of Scottish pairs were associated with non-moorland habitats, such as mature conifer plantations and scrub/brash.

Conclusions There was a substantial increase in the breeding population in most regions of the UK and Isle of Man between 1998 and 2004, possibly aided by increased use of non-moorland habitats. However, populations declined in upland areas of southern and eastern Scotland and northern England. Continuing illegal persecution arising from perceived conflicts between breeding Hen Harriers and driven grouse shooting may be a major cause of these regional declines.     

Breeding status of Merlins Falco columbarius in the UK in 2008

Capsule The third national Merlin survey estimated a UK population of 1162 breeding pairs (95% CI: 891–1462).

Aims To estimate the number of breeding Merlins (with associated 95% confidence intervals) in the UK and the four countries (Scotland, England, Wales and Northern Ireland), and to compare these with the relevant estimates from the 1993–94 Merlin survey. In addition, to calculate estimates of change for several regional populations with complete survey coverage during both national surveys.

Methods A subset of 10-km squares (Raptor Study Group squares and randomly sampled squares) was surveyed across the breeding distribution of Merlins in the UK using standardised methods devised during the 1993–94 national survey.

Results The population estimate for Merlins in the UK was 1162 breeding pairs, and in Britain was 1128 pairs (95% CI: 849–1427), which although 13% lower, was not significantly different from the British estimate of the 1993–94 survey. Scotland held the bulk (733 pairs) of the UK Merlin population, and smaller numbers of 301 pairs, 94 pairs and 32 pairs were estimated for England, Wales and Northern Ireland, respectively. The population estimate for Wales may have been biased upwards by low coverage in the south of the country. Marked declines were noted in several regional Merlin populations, particularly in areas of northern England.

Conclusions The 2008 Merlin survey suggests that the population in Britain has remained relatively stable since 1993–94, but with local declines, particularly in northern England. Currently, little is known about important drivers of regional population change in Merlins, but changes in land-use, prey populations and climate are likely to be important factors.