The effects of woodland habitat and biogeography on blue tit Cyanistes caeruleus territory occupancy and productivity along a 220 km transect

Abstract

The nesting phenology and productivity of hole-nesting woodland passerines, such as tit species (Paridae), has been the subject of many studies and played a central role in advancing our understanding of the causes and consequences of trophic mismatch. However, as most studies have been conducted in mature, oak-rich (Quercus sp.) woodlands, it is unknown whether insights from such studies generalise to other habitats used by woodland generalist species. Here we applied spatial mixed models to data collected over three years (2014)(2015)(2016) from 238 nestboxes across 40 sites -that vary in woodland habitat and elevation -along a 220 km transect in Scotland. We evaluate the importance of habitat, biogeography and food availability as predictors of mesoscale among-site variation in blue tit Cyanistes caeruleus nestbox occupancy and two components of productivity (clutch size and fledging success). We found that habitat was not a significant predictor of occupancy or clutch size but that occupancy exhibited pronounced biogeographic trends, declining with increasing latitude and elevation. However, fledging success, defined as the proportion of a clutch that fledged, was positively correlated with site level availability of birch, oak and sycamore, and tree diversity. The lack of correspondence between the effects of habitat on fledging success versus occupancy and clutch size may indicate that blue tits do not accurately predict the future quality of their breeding sites when selecting territories and laying clutches. We found little evidence of spatial autocorrelation in occupancy or clutch size, whereas spatial autocorrelation in fledging success extends over multiple sites, albeit non-significantly. Taken together, our findings suggest that the relationship between breeding decisions and breeding outcomes varies among habitats, and we urge caution when extrapolating inferences from one habitat to others.

Gradients in richness and turnover of a forest passerine's diet prior to breeding: A mixed model approach applied to faecal metabarcoding data

“…Fieldwork was conducted during the springs of 2014 and 2015 at 39 predominantly deciduous woodland sites that together comprise a 220 km latitudinal transect in Scotland (Shutt, Bolton, Benedicto Cabello, Burgess, & Phillimore, 2018). At each site there were six Schwegler 1B 26 mm hole nestboxes distributed at approximately 40 m intervals.…”

“…Latitude (site range 55.98–57.88°N) and elevation (10–433 m) were obtained for each nestbox (Shutt et al, 2018). Site‐level habitat metrics were derived from surveys of numbers of trees of different genera belonging to three size classes (based on girth at breast height) within 15 m radius of each nestbox, as described in Shutt et al (2018).…”

The environmental predictors of spatio-temporal variation in the breeding phenology of a passerine bird

“…This study was conducted along a 220 km transect from Edinburgh (55°98 0 N, 3°40 0 W) to Dornoch (57°89 0 N, 4°08 0 W) in Scotland, incorporating 40 deciduous woodland sites (electronic supplementary material, figure A1) which varied in elevation (8-440 m above sea level) [42]. Each site had six nest-boxes (26 mm hole Schwegler 1B) used by breeding blue tits during 2014-2018.…”

A Spatial Perspective on the Phenological Distribution of the Spring Woodland Caterpillar Peak

“…Here we sample caterpillars across 40 sites and 220 km (Shutt et al 2018), identifying species via the cytochrome oxidase subunit I (COI) genetic barcode. We address three major aims to understand how the caterpillar community (and its phenological distribution) varies across space and tree species.…”