Leitao, A.; van Dooren, T. J. M.; Riebel, K.: Temporal variation in chaffinch Fringilla coelebs song: Interrelations between the trill and flourish. Journal of Avian Biology 35 (3), pp. 199 - 203 (2004)

Leitner, S.; Catchpole, C. K.: Syllable repertoire and the size of the song control system in captive canaries (Serinus canaria). Journal of Neurobiology 60 (1), pp. 21 - 27 (2004)

Leitner, S.; Voigt, C.: Der Kanarengirlitz - ein Inselbewohner. Gefiederte Welt 128, pp. 248 - 249 (2004)

Levinson, H. Z.; Levinson, A. R.: Wehrhafte Gliederfüßer als heilige Tiere in Altägypten. Naturwissenschaftliche Rundschau 57 (3), pp. 122 - 134 (2004)

Lindström, K. M.; Foufopoulos, J.; Parn, H.; Wikelski, M.: Immunological investments reflect parasite abundance in island populations of Darwin's finches. Proceedings of the Royal Society B: Biological Sciences 271 (1547), pp. 1513 - 1519 (2004)

Mackie, R. I.; Rycyk, M.; Ruemmler, R. L.; Aminov, R. I.; Wikelski, M.: Biochemical and microbiological evidence for fermentative digestion in free-living land iguanas (Conolophus pallidus) and marine iguanas (Amblyrhynchus cristatus) on the Galapagos archipelago. Physiological and Biochemical Zoology 77 (1), pp. 127 - 138 (2004)

Martin, L. B.; Pless, M.; Svoboda, J.; Wikelski, M.: Immune activity in temperate and tropical house sparrows: A common-garden experiment. Ecology 85 (8), pp. 2323 - 2331 (2004)

Mettke-Hofmann, C.; Gwinner, E.: Differential assessment of environmental information in a migratory and a nonmigratory passerine. Animal Behaviour 68 (5), pp. 1079 - 1086 (2004)

Møller, A. P.; Berthold, P.; Fiedler, W.: The challenge of future research on climate change and avian biology. Advances in Ecological Research 35, pp. 237 - 245 (2004)

Mueller, J. C.; Andreoli, C.: Plotting haplotype-specific linkage disequilibrium patterns by extended haplotype homozygosity. Bioinformatics 20 (5), pp. 786 - 787 (2004)

Müllner, A.; Linsenmair, K. E.; Wikelski, M.: Exposure to ecotourism reduces survival and affects stress response in hoatzin chicks (Opisthocomus hoazin). Biological Conservation 118 (4), pp. 549 - 558 (2004)

Pain, D. J.; Green, R. E.; Gießing, B.; Kozulin, A.; Poluda, A.; Ottosson, U.; Flade, M.; Hilton, G. M.: Using stable isotopes to investigate migratory connectivity of the globally threatened aquatic warbler Acrocephalus paludicola. Oecologia 138 (2), pp. 168 - 174 (2004)

Partecke, J.; Van't Hof, T. J.; Gwinner, E.: Differences in the timing of reproduction between urban and forest European blackbirds (Turdus merula): Result of phenotypic flexibility or genetic differences? Proceedings of the Royal Society B: Biological Sciences 271 (1552), pp. 1995 - 2001 (2004)

Peters, A.; Delhey, K.; Denk, A.; Kempenaers, B.: Trade-offs between immune investment and sexual signaling in male mallards. American Naturalist 164 (1), pp. 51 - 59 (2004)

Peters, A.; Denk, A.; Delhey, K.; Kempenaers, B.: Carotenoid-based bill colour as an indicator of immunocompetence and sperm performance in male mallards. Journal of Evolutionary Biology 17 (5), pp. 1111 - 1120 (2004)

Peters, G.; East, M. L.; Herzel, H.; Henschel, J. R.; Mills, M. G. L.; Wilhelm, K.; Hofer, H.: Spotted hyaena whoops: Frequent incidence of vocal instabilities in a mammalian loud call. Bioacoustics - The International Journal of Animal Sound and Its Recording 14 (2), pp. 99 - 109 (2004)

Petracci, P. F.; Delhey, K.: Nesting attempts of the Cliff Swallow Petrochelidon pyrrhonota in Buenos Aires Province, Argentina. Ibis 146 (3), pp. 522 - 525 (2004)

Pophof, B.: Pheromone-binding proteins contribute to the activation of olfactory receptor neurons in the silkmoths Antheraea polyphemus and Bombyx mori. Chemical Senses 29 (2), pp. 117 - 125 (2004)

Pulido, F.; Coppack, T.: Correlation between timing of juvenile moult and onset of migration in the blackcap, Sylvia atricapilla. Animal Behaviour 68 (1), pp. 167 - 173 (2004)

Rattenborg, N. C.; Mandt, B. H.; Obermeyer, W. H.; Winsauer, P. J.; Huber, R.; Wikelski, M.; Benca, R. M.: Migratory sleeplessness in the white-crowned sparrow (Zonotrichia leucophrys gambelii). PLoS Biology 2 (7), pp. 924 - 936 (2004)