Autumn migratory orientation and route choice in early and late dunlins Calidris alpina captured at a stopover site in Alaska

ABSTRACT We investigated the migratory orientation of early and late captured dunlins, Calidris alpina, by recording their migratory activity in circular orientation cages during autumn at a staging site in southwest Alaska and performed route simulations to the wintering areas. Two races of dunlins breeding in Alaska have different wintering grounds in North America (Pacific Northwest), and East Asia. Dunlins caught early in autumn (presumably Calidris alpinapacifica) oriented towards their wintering areas (east-southeast; ESE) supporting the idea that they migrate nonstop over the Gulf of Alaska to the Pacific Northwest. We found no difference in orientation between adult and juveniles, nor between fat and lean birds or under clear and overcast skies demonstrating that age, energetic status and cloud cover did not affect the dunlins’ migratory orientation. Later in autumn, we recorded orientation responses towards south-southwest suggesting arrival of the northern subspecies Calidris alpinaarcticola at our site. Route simulations revealed multiple compass mechanisms were compatible with the initial direction of early dunlins wintering in the Pacific Northwest, and for late dunlins migrating to East Asia. Future high-resolution tracking would reveal routes, stopover use including local movements and possible course shifts during migration from Alaska to wintering sites on both sides of the north Pacific Ocean.

Samvariation mellan systematiska räkningar och spontan rapportering av rastande vadare i Getteröns naturreservat

This paper is an attempt to describe how strong the covariation is between systematic counts and spontaneous reporting of staging waders at the Getterön Nature Reserve in southwestern Sweden. The material is based on systematic and spontaneous observations of twelve species of waders, made on the same days during the autumn migration in July–October 2010–2019. There is a significant positive correlation between the two methods for nine of twelve species. However, there is a large variation in the strength of the correlations, with the strongest correlation seen for Dunlin Calidris alpina. The Wood Sandpiper Tringa glareola, Green Sandpiper Tringa ochropus, and Little Stint Calidris minuta, on the other hand, show no significant correlations. This shows the difficulties in evaluating quantitative data of the wader occurrence at stopover areas such as Getterön. The variation in correlation between count methods between different species entails an uncertainty, which is probably due to low reliability in the spontaneous reporting. Thus, in the case of studies of staging waders based solely on spontaneous data, caution should be exercised.

Survival during the pre-fledging period rather than during post-fledging drives variation in local recruitment of an endangered migratory shorebird, the Southern Dunlin Calidris alpina schinzii

The declines in wet-grassland breeding shorebird populations are considered to mainly result from changes in reproduction. While there is plenty of information on nest survival, little reliable information exists on local recruitment due to confounding effects of permanent emigration. Furthermore, few studies have been able to study the roles of pre- and post-fledging survival on local recruitment. Therefore, it is unclear whether local recruitment of young reflects conditions at the breeding sites or at non-breeding sites. We studied an isolated population of the endangered Southern Dunlin (Calidris alpina schinzii) breeding on the west coast of Sweden to examine (1) brood survival (probability of at least one chick fledging) by following broods fates and (2) local recruitment (survival from hatching to 1 year old) using capture-recapture data. We then examined how much of the annual variation in juvenile survival was explained by variation in brood survival. Brood survival was on average 0.58 (annual range 0.08–1.00) and explained 64% of variation in annual local recruitment. Still local recruitment was rather high for a shorebird (0.17, SE = 0.023), which reflects the isolated nature of the study population. Our results suggest that local recruitment seems to be mainly constrained by chick survival during the pre-fledging period. Therefore, management of breeding sites leading to increased brood survival, e.g., reducing predation on chicks, should have strong impacts on local recruitment and local population growth.

TAXONOMIC NOTES ON FEATHER MITE SPECIES (ACARIFORMES: ANALGOIDEA) DESCRIBED BY ADOLF EDUARD GRUBE

The study presents the results of our re-investigation of feather mite species described by A. E. Grube in 1859 in the genus Dermaleichus Koch, 1841. Grube’s paper has been overlooked by most of the 19th and 20th century acarologists. Based on the study of the syntypes of four Dermaleichus species described by the above author, we provide taxonomic comments on them and new synonymies. We conclude the names of three species are valid (senior) synonyms, while one name is a junior synonym. Alloptes (Alloptes) tringae (Grube, 1859) comb. n. (Alloptidae) from Calidris alpina (Charadriiformes: Scolopacidae) is a new senior synonym of Alloptes (s. str.) crassipes (Canestrini, 1878) syn. n.; Analges tergisetis (Grube, 1859) comb. n. (Analgidae) from Pica pica (Passeriformes: Corvidae) is a new senior synonym of Analges corvinus Robin, 1877 syn. n.; Picalgoides caudilobus (Grube, 1959) comb. n. (Psoroptoididae) from Dendrocoptes medius (Piciformes: Picidae) is an older synonym of Dermaleichus picimajoris Buchholz, 1869, D. picipubescentis Packard, 1869, Analges serratilobus Giebel, 1871 and Analges socialis Robin, 1877 (synonymized by Oudemans in 1939, but overlooked by subsequent researchers). Dermaleichus albicillae Grube, 1859 syn. n. from Haliaeetus albicilla (Accipitriformes: Accipitridae) is a junior synonym of Pandionacarus fuscus (Nitzsch, 1818) (Avenzoariidae), a common parasite of Pandion haliaetus (Accipitriformes: Pandionidae).

Genotyping-by-sequencing reveals genomic homogeneity among overwintering Pacific Dunlin (Calidris alpina pacifica) aggregations along the Pacific coast of North America

Information on how migratory populations are genetically structured during the overwintering season of the annual cycle can improve our understanding of the strength of migratory connectivity and help identify populations as units for management. Here, we use a genotype-by-sequencing approach to investigate whether population genetic structure exists among overwintering aggregations of the Pacific Dunlin subspecies (Calidris alpina pacifica) sampled at 2 spatial scales (within and among overwintering sites) in the eastern Pacific Flyway. Genome-wide analyses of 874 single nucleotide polymorphisms across 80 sampled individuals revealed no evidence for genetic differentiation among aggregations overwintering at 3 locations within the Fraser River Estuary (FRE) of British Columbia. Similarly, comparisons of aggregations in the FRE and those overwintering in southern sites in California and Mexico indicated no genetic segregation between northern and southern overwintering areas. These results suggest that Pacific Dunlin within the FRE, Sacramento Valley (California), and Guerrero Negro (Mexico) are genetically homogeneous, with no evident genetic structure between sampled sites or regions across the overwintering range. Despite no evidence for differentiation among aggregations, we identified a significant effect of geographical distance between sites on the distribution of individual genotypes in a redundancy analysis. A small proportion of the total genotypic variance (R2 =0.036, P = 0.011) was explained by the combined effect of latitude and longitude, suggesting weak genomic patterns of isolation-by-distance that are consistent with chain-like migratory connectivity between breeding and overwintering areas. Our study represents the first genome-scale investigation of population structure for a Dunlin subspecies and provides essential baseline estimates of genomic diversity and differentiation within the Pacific Dunlin.

КУЛИКИ ГОРНОГО КРЫМА, "НАУКА ЮГА РОССИИ"

По результатам исследований 1976-2018 гг. (1,1 тыс. локальных наблюдений и количественных учетов) рассмотрен видовой состав, распространение, численность, характер и сроки пребывания куликов в горном Крыму. Выявлено 36 видов, не отмечены указанные ранее Charadrius hiati cula. Pluvialis apricari а и Glareola nordmanni. Гнездятся 7 видов (Burhims oedicnemus. Charadrius dubius. I anellus vanellus. Himantopus himantopus. Tringa totanus. Actitis hypoleucos. Scolopax rusticola), в том числе 4 в предгорьях, 5 на востоке Южного берега Крыма и 3 в области Главной гряды. Большинство видов распространено спорадически и малочисленно по причине дефицита подходящих местообитаний. Обычен и широко распространен Charadrius dubius. В миграционные периоды встречается 35 видов (31 весной и 26 осенью); пики видового разнообразия мигрантов наблюдаются в третьей декаде апреля и третьей декаде августа. На летних кочевках обычны Actitis hypoleucos и Tringa ochropus. Зимуют 8 видов - Vanellus vanellus. Tringa ochropus. T. totanus. Calidris alpina, C. canutus. Lymnocryptes minimus. Gallinago gallinago. Scolopax rusticola, последний обычен. Со второй половины XX века в фауне куликов Крыма в общем и горной его части в частности произошли существенные изменения. Обнаружено II ранее не зарегистрированных видов: 10 мигрирующих (Vanellochettusia leucura. Arenaria interpres. Haematopus ostralegus. Tringa stagnati lis. Xenus cinereus. Calidris ferruginea, C. alba. Limicola falcinellus. Numenius phaeopus. Glareola pratincola) и 1 зимующий (Calidris canutus). Подтверждено пребывание 8 видов, ранее отмеченных только в XIX - начале XX века; 2 вида (Himantopus himantopus. Tringa totanus) впервые обнаружены на гнездовании и 3 вида (Vanellus vanellus. Tringa nebularia. T. totanus) - во время осенней миграции.