Opportunistic use of a wool-like artificial material as lining of Tit (Paridae) nests

The lining material is a key element of bird nests primarily serving as insulation for the adult, eggs and/or chicks but collection of such material will have an energetic cost. This study investigated the nest building effort of four species of tit (Paridae) in an English wood by determining the use of colored, wool-like artificial nest lining material over the period 2000-2010. The distances that birds carried the material from source to nest was recorded for each nest as an indirect measure of the energetic cost of collection of nest material by individual birds. Birds did not always use nest material from the nearest source to their nest and some birds collected material from 2, 3 or 4 well-separated sources. There was no detectable color preference in choice of material and few birds would travel more than 200 m to gather the material. Use of the material appeared to depend on the species. Within defined areas around material dispensers not all individual Great Tits (Parus major) used the artificial material and, for all species examined, the proportion of birds using the material declined with increasing distance between source and nest. Use of artificial material suggested that selection of nest materials was probably opportunistic but also reflected the preference of these species for a wool-like nest-lining

Should rehabilitated hedgehogs be released in winter? A comparison of survival, nest use and weight change in wild and rescued animals

The rehabilitation of sick or injured wildlife and their subsequent release back into the wild is considered important, not only for the welfare of the individual animal but also for the conservation and management of endangered and threatened wildlife. The European hedgehog Erinaceus europaeus has declined by 25% in Britain over the last decade and is the most common mammal admitted to wildlife rehabilitation centres in Britain, with a large proportion of individuals admitted to gain body weight overwinter prior to release in the spring. Consequently, many thousands of hedgehogs are housed overwinter which incurs significant costs for rehabilitation centres, and has potentially animal welfare issues, such as, stress in captivity, reintroduction stress, increased mortality risk and impaired or altered behaviour. To determine if releasing rehabilitated hedgehogs during autumn and winter had an effect on their survival, body weight or nesting behaviour, we compared these factors between 34 rehabilitated hedgehogs with 23 wild hedgehogs across five sites in England over four different winters. Overwinter survival was high for both wild and rehabilitated hedgehogs, with a significant decrease in survival across both groups when hedgehogs became active post hibernation in spring. We found no differences in the survival rates up to 150 days post release, in weight change, or nest use between wild- and winter-released rehabilitated hedgehogs. Our results suggest that under the correct conditions, rehabilitated hedgehogs can be released successfully during winter, therefore avoiding or reducing time in captivity