Hawk and Owl Trust-sponsored research into the decline of the little owl has come to the end of its second year.
Postgraduate student Emily Joachim's research, continuing to draw on the Imber Conservation Group Nestbox Project (Wiltshire, UK) has two major strands: post-fledging survival and dispersal; and the feeding ecology of the little owl.
Fledgling survival and dispersal
Leg-mount radio-tags were fitted to a further 11 juvenile little owls during 2009. After five months, when the radio-tag batteries ran out, nine were known to have survived. One juvenile was killed by a sparrowhawk and the other was mobbed to death by corvids. Emily is hopeful that some of the remaining juveniles will survive the harsh winter to breed in 2010.
Three of the nine survivors took their flight of independence early enough to be tracked, and all three dispersed within 2.3 km of where they were hatched.
Feeding ecology
Two Master of Science research students, Jess Neumann and Kimberly Page, examined little owl prey availability and prey selection during 2008 and 2009. Preliminary results suggest that little owls are not foraging at random. For example, the little owl shows a preference for larger carabid beetle species; however, at one site where large carabid species were abundant in arable fields, they were not common in their pellets. This suggests that vegetation composition and sward height could be restricting the little owls’ access to potentially valuable prey resources.
Passive Integrated Transponder (PIT) tag technology is also being used to examine the foraging ecology. These tags were fitted to little owl pairs and tag readers installed at nestbox entrances. We are using this technology to learn more about how frequently parents visit nestlings and other aspects of foraging ecology, such as peaks in feeding rates and how these vary throughout the year and in different habitats.
Following an idea Emily had in 2008, this technology will be combined with nextbox cameras to further our understanding of how often the young are fed during the nesting period, juvenile and adult diet and little owl behaviour within the nesting cavity.
Emily Joachim’s research is supervised by Dr Graham Holloway at The University of Reading and her fieldwork is supervised by Major Nigel Lewis MBE. The PhD is funded by a Biotechnology and Biological Sciences Research Council (BBSRC) studentship and is sponsored by the Hawk and Owl Trust and the World Owl Trust. Natural Research Limited and Andy Rouse’s & Paramo’s joint ‘Aspira Fund’ have funded the PIT tag equipment.
