Age‐dependent prospecting and recruitment to a breeding colony of Short‐tailed Shearwaters Puffinus tenuirostris

Abstract

In a small colony of Short‐tailed Shearwaters Puffinus tenuirostris, monitored annually since 1947, many of the young ringed as nestlings returned to their natal colony for one or more years before breeding for the first time. These ‘prospectors’ were first recorded at 4.1 ± 0.1 (range 2–7) years old; they started breeding at 7.0 ± 0.2 (4–14) years old. Overall, 31% of all prospectors bred on their natal island with no significant annual variation in this proportion. However, 8% of all natal recruits started breeding without having been recorded prospecting and bred first when significantly younger (5.6 ± 0.4 years old) than those first recorded prospecting. Shearwaters which subsequently bred at their natal colony started prospecting when significantly older (4.3 ± 0.1) than those that did not breed at their natal colony (4.0 ± 0.1 years). Non‐natal recruits spent significantly less time prospecting (1.0 ± 0.1 years) than prospectors born on the island (1.9 ± 0.1 years). The shearwaters appeared to become progressively more faithful to the colony during their prospecting period.

The impact of the sandeel fishery closure on seabird food consumption, distribution, and productivity in the northwestern North Sea

“…We assumed that immature birds within 2 years of mean recruitment age were present in the study area on the basis that colony attendance during the breeding season commences in the years prior to recruitment (e.g. Bradley et al 1999). The component of the population represented by each attending immature age class was summed and expressed as a proportion of the total number of breeding adults.…”

Breeding parameters of the Sooty Shearwater (Ardenna grisea) on Long Island, New Zealand

“…the chick no longer in the burrow). Burrows initially considered active based on only a single record of an adult Sooty Shearwater present early in the breeding season and with no confirmation of laying were removed from analysis as they may have been adults prospecting for a burrow (Bradley et al 1999) or otherwise not breeding (Serventy 1967).…”

First confirmed record of a Common TernSterna hirundobreeding at one year of age

“…Such late and transient breeding attempts are easy to miss in most colony studies, where the majority of study birds lay early or during peak colony laying dates (Bradley et al 1999). Additionally, because our one-year-old shared more plumage characteristics with second-summer than first-summer birds, first-time breeding by oneyear-old Common Terns may be easily overlooked.…”

“…Although essential for demographic modelling and some life-history studies, determining age at first breeding for seabirds is challenging because of their longevity, migratory habits and colonial breeding (Harris et al 1994). Locating first-time breeders in large colonies may be difficult: these birds breed late in the season (Bradley et al 1999, Ludwigs & Becker 2005), yet most studies occur earlier (to facilitate large samples that best represent colony-wide breeding), and first-time breeders often fail quickly and so are less likely to be observed (Harris et al 1994).…”