Southern Crested Caracara (Caracara plancus) Science Article 1 abstract We observed Crested caracaras (Caracara plancus) consuming and dispersing fruits of the palm Attaleaphalerata at Pantanal, Brazil. We reviewed the literature of seed dispersal by raptors and suggest that raptors may affectseed dispersal by three different paths: secondary seed dispersal by preying on frugivorous birds, primary […]
International single species Action planfor the Conservation of the Northern Bald Ibis
Southern Bald Ibis (Geronticus calvus) Science Article 1 abstract The Northern Bald Ibis Geronticus eremita has undergone a long history of decline over at least four centuries, having been distributed over much of north and northeast Africa and the Middle East. Two distinct populations have been identified which are genetically distinct. The main western population […]
Evidence of conspecific nest parasitism and egg discrimination in the sora
Sora (Porzana carolina) Science Article 2 abstract Conspecific nest parasitism (CNP) is relatively frequent among precocial species and several hypotheses for this patter have been suggested (Rohwer and Freeman 1989, Lyon and Eadie 1991, Sorenson 1992). I report here observations made at the nest of a Sora, Porzana carolina, which suggest both the occurrence of […]
NESTING SUCCESS AND SURVIVAL OF VIRGINIA RAILS AND SORAS
Sora (Porzana carolina) Science Article 1 abstract Lack of estimates of nesting success and annual survival of North American rails limits our ability to monitor rail populations, regulate harvest levels, and institute recovery programs. We here present Virginia Rail (Rallus limicola) and Sora (Porzana carolina) population trends from Breeding Bird Surveys (BBS) throughout North America
Demographic mechanisms of the population decline of the song thrush Turdus philomelos in Britain
Song Thrush (Turdus philomelos) Science Article 3 abstract In Britain, the song thrush Turdus philomelos is categorized as a species of high national conservation concern because of a large population decline during the last three decades. We calculated a series of annual national population estimates for woodland and farmland habitats combined for the period 1964-2000. […]
Blue eggs do not reduce nest predation in the song thrush,Turdus philomelos
Song Thrush (Turdus philomelos) Science Article 2 abstract Many passerine birds with open cup-shaped nests lay blue or blue-green eggs. In thrushes, blue eggs may be cryptic and provide camouflage by imitating spots of light on green leaves. Alternatively, egg coloration may be selectively neutral because nest predators detect nests and not eggs, or it […]
Post-breeding dispersal, breeding site fidelity and migration/wintering areas of migratory populations of Song Thrush Turdus philomelos in the Western Palearctic
Song Thrush (Turdus philomelos) Science Article 1 abstract Song Thrush Turdus philomelos ring recovery data gathered over 90 years in central, north and east Europe were analysed in their breeding zones and in 14 migration/wintering areas in Europe, North Africa and the Near East. Few post-breeding movements were over 20 km before the end of […]
Partial song matching in an eastern population ofsong sparrows, Melospiza melodia
Song Sparrow (Melospiza melodia) Science Article 2 abstract One hypothesis for the function of vocal repertoires in songbirds is that singing multiple song typesfacilitates song matching, a behaviour in which one male replies to a rival’s song with a song of the sametype. In eastern populations of song sparrows, low levels of whole song sharing […]
The social interaction role of song in song sparrows: implications for signal design
Song Sparrow (Melospiza melodia) Science Article 17 abstract Many territorial songbirds use singing as an interactive social signal to reduce inter-neighbor aggression. Communicationtheory predicts that territorial songbirds may use repertoires of signals to indicate graded levels of aggressive motivation.This theory is supported in song sparrows, a species that uses several different song-based signals such as […]
Correlation of song learning and territory establishment strategiesin the song sparrow
Song Sparrow (Melospiza melodia) Science Article 12 abstract In a field study, we show that a young song sparrow (i) selects his songs from three or four older birds who have neighboring territories, (ii) preferentially learns song types that these tutor neighbors share, and (ui) ultimately sets up his territory next to, or replaces, one […]