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Second radio tracking study of Ring Ouzel Turdus torquatus

This radio tracking study of Ring Ouzels is being carried out in upper Glen Esk, 50km north of Dundee. The ring ouzel populations in Glens Lee, Mark and Effock have been studied since 1992, data from 1992 to 2000 showed that the area contained a stable breeding population (Arthur & White 2001, Burfield 2002). However, data from last season suggests that this population is now experiencing a decline alongside many other UK Ring Ouzel populations.

The birds arrived late on territories this season, probably due to the cold weather in April and May so consequently egg laying has begun later than in previous years.

Fieldwork carried out so far this season has involved resurveying previously occupied territories in Glens Lee, Mark and Effock. Early indications are there is a slightly better occupancy than last year. To date, around 30 Ring Ouzel chicks have been ringed and colour ringed using unique colour combinations allowing individual identification in the field. In addition to this, a radio tag has been fitted to an adult male Ring Ouzel, which was successfully trapped on the nest. Several visits have been made to gather data on its behaviour. This is the early stage of gathering information from the tags. Other nests have been identified allowing future attempts to be made at nest trapping adults. Data from radio tagged adults may also be invaluable for finding fledged young, allowing mist netting attempts to be made in order to fit tags on juveniles. Hopefully this method will allow a family party to be followed throughout the season.

The male already fitted with a radio tag has remained on territory and it is hoped it will have a second brood. The plan then is to determine home range sizes and chick provisioning rate with data from radio tracking. Information will be gathered on where birds are foraging. This will allow pitfall traps and core samples to be taken from appropriate areas, determining the invertebrate communities in areas selected by foraging Ring Ouzel. After breeding territories dissolve, the radio tags hopefully will provide an invaluable tool for studying post-breeding dispersal. This is an area where there is a lack of knowledge; most of the literature on Ring Ouzel concerns their breeding biology. Any tags not fitted during the breeding season will be attached to birds, which will be caught late summer when they congregate on berries prior to migration. This will add to data collected last year, helping determine habitat requirements of Ring Ouzel prior to migration.

There have been several recorded instances of nest predation in Glen Esk this season. More concernedly, data collected has shown that the population of Ring Ouzel in Glen Esk is experiencing a decline. The lack of birds in Glen Esk has hampered attempts to attach radio tags. It is important that work is carried out in subsequent years to determine if the observed decline in Glen Esk is a seasonal decline or whether it is part of the more widespread general decline of Ring Ouzel in the U.K. Hopefully information gained from radio tracking studies of Ring Ouzel will contribute to our knowledge of this understudied species, allowing conservation efforts to be targeted at the Ring Ouzels precise requirements.

Submitted by Dawn Thomson and David Arthur (Tay RG received a substantial grant form the SITA / Tayside Biodiversity Fund to assist in this work and we would like to record out thanks to them for their support, particularly Catherine Lloyd).