1. Which birds participate in mass concentrations of Bramblings Fringilla montifringilla?—Ring recoveries, biometry, age and sex composition

   • Lukas Jenni

   Original Article Open access 30 July 2021 Pages: 1 - 17

   

2. Cross the sea where it is narrowest: migrations of Pacific Swifts (Apus pacificus) between Sakhalin (Russia) and Australia

   • Pavel Ktitorov
   • Wieland Heim
   • Luke Gibson

   Original Article 23 July 2021 Pages: 19 - 26

   

3. Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

   • Jorge García-Macía
   • Javier Vidal-Mateo
   • Vicente Urios

   Original Article Open access 29 July 2021 Pages: 27 - 36

   

4. Migration and non-breeding ecology of the Yellow-breasted Chat Icteria virens

   • Kristen A. Mancuso
   • Karen E. Hodges
   • Christine A. Bishop

   Original Article Open access 15 October 2021 Pages: 37 - 50

   

5. Underestimated scale of songbird offshore migration across the south-eastern North Sea during autumn

   • Vera Brust
   • Ommo Hüppop

   Original Article Open access 13 October 2021 Pages: 51 - 60

   

6. Fuel management, stopover duration and potential flight range of pied flycatcher Ficedula hypoleuca staying in South-West France during autumn migration

   • Jean-Marc Fourcade
   • Philippe Fontanilles
   • Laurent Demongin

   Original Article 16 November 2021 Pages: 61 - 70

   

7. All-season space use by non-native resident Mandarin Ducks (Aix galericulata) in northeastern Germany

   • Ulrike E. Schlägel
   • Wolfgang Mädlow

   Original Article Open access 20 October 2021 Pages: 71 - 82

   

8. Female breeding dispersal to higher quality habitats in a philopatric top predator

   • Andreas Otterbeck
   • Andreas Lindén
   • Patrik Byholm

   Original Article Open access 10 December 2021 Pages: 83 - 92

   

9. Contrasting patterns of geographical song variation in two closely related passerine species with a simple song

   • Ivana Czocherová
   • Lucia Rubáčová
   • Tereza Petrusková

   Original Article 14 August 2021 Pages: 93 - 104

   

10. Vocal behavior and microgeographic variation in song types in a Neotropical songbird

    • Juliana Rodríguez-Fuentes
    • Carlos Daniel Cadena
    • Jorge Enrique Avendaño

    Original Article 27 September 2021 Pages: 105 - 119

    

11. Vocal behaviour of Sclater’s Wrens, a duetting Neotropical songbird: repertoires, dawn chorus variation, and song sharing

    • Marcos Quiroz-Oliva
    • J. Roberto Sosa-López

    Original Article 20 October 2021 Pages: 121 - 136

    

12. Diet of nestling Barn Swallows in an agroecosystem: insights from fecal DNA barcoding and feather stable isotopes (δ¹³C, δ¹⁵N)

    • Jackson W. Kusack
    • Greg W. Mitchell
    • Keith A. Hobson

    Original Article 23 July 2021 Pages: 137 - 150

    

13. Essential amino acid requirements of granivorous and omnivorous songbirds and the provision of natural foods

    • Lillie A. Langlois
    • Scott R. McWilliams

    Original Article 26 July 2021 Pages: 151 - 163

    

14. Changing places: spatial ecology and social interactions of female and male Montagu’s Harrier (Circus pygargus) in the Spanish Extremadura

    • Brigitte Berger-Geiger
    • Georg Heine
    • C. Giovanni Galizia

    Original Article Open access 03 August 2021 Pages: 165 - 179

    

15. Head and body orientation of the White Stork Ciconia ciconia during incubation: effect of wind, apex predators and power lines

    • Adam Zbyryt
    • Łukasz Jankowiak
    • Piotr Tryjanowski

    Original Article Open access 28 July 2021 Pages: 181 - 189

    

16. Chemical analysis reveals sex differences in the preen gland secretion of breeding Blue Tits

    • Barbara A. Caspers
    • Reinaldo Marfull
    • Peter Korsten

    Original Article Open access 11 August 2021 Pages: 191 - 198

    

17. Differences in transcription regulation of diurnal metabolic support to physiologically contrasting seasonal life-history states in migratory songbirds

    • Aakansha Sharma
    • Subhajit Das
    • Vinod Kumar

    Original Article 30 August 2021 Pages: 199 - 212

    

18. Body composition of American Woodcock during fall staging: a validation of the non-invasive deuterium dilution method

    • Clayton L. Graham
    • Scott R. McWilliams

    Original Article 26 September 2021 Pages: 213 - 222

    

19. Linking environmental indicators to blood, feather and claw δ¹⁸O in the Saffron Finch (Sicalis flaveola) in the central Brazilian savannas

    • Fábio José Viana Costa
    • Keith A. Hobson
    • Gabriela Bielefeld Nardoto

    Original Article 19 November 2021 Pages: 223 - 234

    

20. Measuring circulating triglycerides in free-living birds: evaluation of a field-usable point-of-care analyzer for American woodcock

    • Christopher M. Roelandt
    • Amber M. Roth
    • Jill C. Witt

    Original Article 25 November 2021 Pages: 235 - 241

    

21. Strong evidence supporting a relationship between colour pattern and apparent survival in common crossbills

    • Blanca Fernández-Eslava
    • Daniel Alonso
    • Juan Arizaga

    Original Article Open access 23 September 2021 Pages: 243 - 249

    

22. Influence of age and body condition on breeding performance in Common Kingfisher Alcedo atthis

    • M. Cepková
    • M. Balážová
    • L. Rubáčová

    Original Article 13 August 2021 Pages: 251 - 261

    

23. Effects of elevated nest box temperature on incubation behaviour and offspring fitness-related traits in the Collared Flycatcher Ficedula albicollis

    • Aneta Arct
    • Rafał Martyka
    • Lars Gustafsson

    Original Article Open access 09 December 2021 Pages: 263 - 272

    

24. No evidence that declining Whinchat Saxicola rubetra are currently limited by the availability of apparently suitable breeding habitat within the UK uplands

    • Andrew J. Stanbury
    • Irena Tománková
    • David J. T. Douglas

    Original Article 02 September 2021 Pages: 273 - 283

    

25. Swallows nesting on buildings showed positive population trends except when having deeply forked tails

    • Masaru Hasegawa
    • Emi Arai

    Original Article 05 October 2021 Pages: 285 - 289

    

26. Genetic diversity and differentiation of the widespread migratory Demoiselle Crane, Grus virgo, on the northern edge of the species’ distribution

    • Elena A. Mudrik
    • Elena I. Ilyashenko
    • Dmitry V. Politov

    Original Article 06 August 2021 Pages: 291 - 299

    

27. Characterization of an extinct seabird colony on the island of Santa Luzia (Cabo Verde) and its potential for future recolonizations

    • Maria Alho
    • José Pedro Granadeiro
    • Paulo Catry

    Original Article 18 August 2021 Pages: 301 - 313

    

28. Cranium of an Eocene/Oligocene pheasant-sized galliform bird from western North America, with the description of a vascular autapomorphy of the Galliformes

    • Gerald Mayr
    • James L. Goedert
    • Renate Rabenstein

    Original Article Open access 15 October 2021 Pages: 315 - 326

    

29. Diversification across the Isthmus of Tehuantepec explains the phylogeographic arrangement of the widespread bright-rumped Attila (Attila spadiceus; Tyrannidae) and reveals the existence of two major lineages

    • Patrícia Mendonça
    • Cleyssian Dias
    • Péricles Sena do Rêgo

    Short Communication 02 September 2021 Pages: 327 - 332

    

30. Trichomonas gallinae infections in the naïve host Montifringilla nivalis subsp. nivalis

    • Sebastian Dirren
    • Stéphanie Borel
    • Fränzi Korner-Nievergelt

    Short Communication Open access 08 November 2021 Pages: 333 - 337