Breeding biology and survival of the Alpine ChoughPyrrhocorax graculus

Abstract

We describe for the first time the breeding biology and survival of the Alpine Chough Pyrrhocorax graculus in different European massifs (Alps and West-Balkan). When all data were pooled, mean clutch and brood sizes were 3.6 eggs (se = 0.1) and 2.6 chicks (se = 0.1), respectively. Fledging success per pair varied between 1 and 4 fledged young per pair (mean 1.9). Survival of the Alpine Chough was estimated with a capture-resighting model using a colourringed population (n = 315 adults) which used human food sources. Adult survival rate varied from 83 to 92%, depending on the flock. This difference could be a consequence of differences in flock composition. No significant difference was detected between male and female survival. Survival of first-year birds (77%) was lower than that of adults. In order to analyse the effect of human food supplied by tourist activities, breeding success and flock structure were compared between 2 alpine populations which either did or did not exploit human food supplied by tourist activities. No difference was found in breeding success or flock composition between the 2 populations.

Pronounced genetic structure and low genetic diversity in European red-billed chough (Pyrrhocorax pyrrhocorax) populations

“…Current published taxonomy recognises a nominate Atlantic coast subspecies P. p. pyrrhocorax (British Isles and Brittany) and a Continental European subspecies P. p. erythrorhamphos (Vaurie 1954;Monaghan 1988), although this distinction was based on few morphological data from unverified museum specimens. The closely-related Alpine chough Pyrrhocorax graculus occurs in mountain regions in Southern and Central Europe, particularly the Alps (Delestrade and Stoyanov 1995).…”

Warm temperatures during cold season can negatively affect adult survival in an alpine bird

“…In each season, individuals were baited with apples and dried grapes, and then captured with cannon nets or clap nets (Delestrade & Stoyanov, 1995a). Captured individuals were ringed with an individual combination of three or four colored plastic bands.…”

“…The second step was the probability of changing age class, which was not estimated and was forced to occur during the first (juvenile to immature) and second (immature to adult) autumn-winter transition. The third and fourth steps corresponded to dispersal probability, which was split into two steps (Grosbois & Tavecchia, 2003) and occurred during the spring-summer transition (Delestrade & Stoyanov, 1995b). The third step modeled an individual's departure probability (i.e., of leaving a summer site given it is still alive), and the fourth step its arrival probability (i.e., of reaching a specific summer site given that it had dispersed at the previous step).…”

A comparative analysis of the breeding biology of the Red‐billed Chough Pynhocorax pyrrhocorax and the Alpine Chough P. graculus coexisting in the Alps

“…Laying and hatching date were determined either by direct observations at the nest or by observing the behaviour of breeders near the nest (nests were checked every day). When nests containing eggs were found, we estimated the laying date, assuming 20 days of incubation, from known dates of hatch (Schifferli & Lang 1940, Delestrade & Stoyanov 1995. Following , fledging success was defined as the mean number of fledglings per successful nest with at least one fledgling.…”

“…Breeding behaviour and parental effort in reproduction of Red-billed and Alpine Choughs have rarely been the focus of previous research and although some aspects of their breeding biology have already been investigated (Bignal et al 1987, Delestrade & Stoyanov 1995, Stillman et al 1998, Laiolo et al 1998, no comparative analysis in areas of syntopy has been produced. Both species are essentially monogamous, with pair bonds of long duration, and sexes co-operate to raise nestlings (Holyoak 1972, Goodwin 1986, Cramp & Perrins 1994.…”