Earlier and more frequent occupation of breeding sites during the non‐breeding season increases breeding success in a colonial seabird

Abstract

Competition for high‐quality breeding sites in colonial species is often intense, such that individuals may invest considerable time in site occupancy even outside the breeding season. The site defense hypothesis predicts that high‐quality sites will be occupied earlier and more frequently, consequently those sites will benefit from earlier and more successful breeding. However, few studies relate non‐breeding season occupancy to subsequent breeding performance limiting our understanding of the potential life‐history benefits of this behavior. Here, we test how site occupancy in the non‐breeding season related to site quality, breeding timing, and breeding success in a population of common guillemots Uria aalge, an abundant and well‐studied colonially breeding seabird. Using time‐lapse photography, we recorded occupancy at breeding sites from October to March over three consecutive non‐breeding seasons. We then monitored the successive breeding timing (lay date) and breeding success at each site. On average, sites were first occupied on the 27th October ± 11.7 days (mean ± SD), subsequently occupied on 46 ± 18% of survey days and for 55 ± 15% of the time when at least one site was occupied. Higher‐quality sites, sites with higher average historic breeding success, were occupied earlier, more frequently and for longer daily durations thereafter. Laying was earlier at sites that were occupied more frequently and sites occupied earlier were more successful, supporting the site defense hypothesis. A path analysis showed that the return date had a greater or equal effect on breeding success as lay date. Pair level occupancy had no effect on breeding timing or success. The clear effect of non‐breeding occupancy of breeding sites on breeding timing and success highlights the benefits of this behavior on demography in this population and the importance of access to breeding sites outside the breeding season in systems where competition for high‐quality sites is intense.

Factors Supporting the Success of Artificial Insemination in Beef Cattle in East Langsa District Langsa City

“…However, it is also possible that breeders with low education may lack certain abilities. This occurs because the level of experience greatly influences how to raise livestock, as knowledge can be acquired through seminars and counseling activities (Bennett et al, 2022). The primary occupation of the breeders with the highest percentage is farming, accounting for 61.90% with 26 people.…”

Carry‐over effects of seasonal migration on reproductive success through breeding site retention in a partially migratory bird

“…While no other empirical studies have directly quantified effects of different migratory tactics on breeding dispersal, wider results are consistent with prior residence effects, especially where competition for breeding sites is high. Higher quality breeding sites were occupied earlier and more often during the non‐breeding season than poorer sites within a common guillemot ( Uria aalge ) colony (Bennett et al., 2022). Residents initiated breeding earlier than migrants in American kestrels ( Falco sparverius , Anderson et al., 2016) and in another population of European shags (Grist et al., 2017).…”

Sex and size shape the ontogeny of partial migration

“…Additionally, residents may have heightened resource‐holding potential when migrants return and attempt to usurp territories (theory of prior residency; Forstmeier, 2002; Jakobsson, 1988; Kokko, 2011). These factors may allow residents to better establish and defend high quality territories, and initiate breeding earlier than migrants (Bennett et al., 2022; Kokko, 1999, 2011). Therefore, under the ATH, sexually mature individuals and the sex responsible for territory acquisition are expected to benefit more from residence than sub‐adults or the mate‐choosing sex and are predicted to have a higher probability of residence (Boyle, 2008; Marques et al., 2010; Morbey & Ydenberg, 2001).…”