Abstract

Vegetation structure influences habitat selection for woodland birds and is a key component determining habitat quality. Here, we demonstrate the application of airborne LiDAR data for organism-habitat modelling. We use data acquired with an Airborne Laser Terrain Mapper (ALTM), recording the elevation of the first and last return signal from a mixed broadleaved woodland in lowland England. We show that reproductive performance in Great Tits (Parus major) and Blue Tits (Parus caeruleus) is related to woodland structure. Since both Great Tits and Blue Tits feed their young on tree-dwelling lepidopteran larvae, canopy structure influences habitat quality via effects on both food abundance and its availability to the parent birds. During the unfavourable weather of 2001, the best foraging conditions for Blue Tits occurred where the canopy was tall and well-developed, but for Great Tits a shorter canopy with a more varied height profile was most favourable. Weather conditions also influence food abundance and birds’ foraging abilities. (Other influential factors include population density, parental quality, and competition for nest sites and food). We show that the nature of the relationship between reproductive success of Great Tits and habitat structure varies temporally in relation to local and regional scale climate drivers. Habitat selection by Great Tits is thus flexible and not determined by fixed preferences. This can be predicted in advance using environmental data. We believe that the remote quantification of habitat quality and its temporal shifts could greatly enhance our ability to predict the impacts of changing environmental pressures on biodiversity.