Breeding phenology, provisioning behaviour, and unusual patterns of life history variation across an anthropogenic heterogeneous landscape

Abstract

Understanding how resource use and life history variation influence a population's response to modified, fragmented landscapes is a major challenge for ecologists. We investigated the phenology, life history decisions and provisioning behaviour of a generalist passerine-the great tit-across a heavily managed woodland landscape. Contrary to most previous studies on this species, reproductive investment and success were lower in deciduous than in coniferous woodland fragments. This could not be explained by differences in provisioning behaviour; instead population density was considerably higher in deciduous woodlands, suggesting birds did not follow an ideal free distribution. Clutch size declined with lay date amongst populations breeding in coniferous woodland fragments, but these populations also displayed pronounced seasonal declines in the proportion of fledglings produced per egg and fledgling mass. In contrast, and against patterns observed in other similar study systems, clutch size did not change with lay date in mixed-species deciduous woodland fragments. Furthermore, the proportion of young fledged and fledgling condition remained stable throughout the season, even though the quality of food provisioned to nestlings increased over the season. Local recruitment was negligible, suggesting that plasticity rather than natural selection played a key role in driving the patterns observed. The unusual patterns we report are likely explained by the fragmented nature of the landscape, and unreliable phenological cues in a mixed-species tree community coupled with low food availability. They contrast with those reported from most other populations situated in continuous woodland, demonstrating that caution is needed when generalising across different contexts and ecosystems.

A time‐lagged association between the gut microbiome, nestling weight and nestling survival in wild great tits

“…Birds were sampled from nine nest box populations across Co. Cork, Ireland, five of these were mixed/deciduous habitats and four were coniferous habitats (see O'Shea et al., 2018). We collected 204 faecal samples from 150 nestling great tits from 54 nests (see below for the number of samples that were successfully sequenced and sample size per developmental stage) for 16S rRNA gene sequencing in order to map the gastrointestinal microbial communities.…”

A longitudinal analysis of the growth rate and mass of tail feathers in a great tit population: ontogeny, genetic effects and relationship between both traits

“…As for many birds, great tits have a predictable moulting strategy involving a number of moulting episodes (Supporting information; Jenni and Winkler 2020a) as follows: 1) fledging period or prejuvenal moult (May–July in our population; O'Shea et al 2018); 2) post‐juvenile moult (July–September); and 3) postbreeding moult during the summer months (June–September). Which feathers are involved in each moult varies.…”

No Evidence for Cross-Contextual Consistency in Spatial Cognition or Behavioral Flexibility in a Passerine

“…Wild-caught great tits (N = 36) from the Bandon Valley, County Cork, Ireland, were brought into captivity, and later released at their capture site upon completing the experiments (O'Shea et al, 2018). Birds were captured using mist nets, and therefore, our sample is likely biased towards trappable individuals (Webster & Rutz, 2020).…”