Abstract from BTO Research Report No 250:

Balmer, D.E., Adams, S.Y. & Crick, H.Q.P. (2000)

Report on Barn Owl Release Scheme Monitoring Project Phase II.
ISBN: 1-904870-67-8

Executive summary

1. A total of 1,737 rings were issued for use on captive-bred Barn Owls between April 1993 and the end of September 2000. Of the birds that have been ringed, 135 have been subsequently recovered.

2. Of the birds that have been recovered, 81% were ringed as pulli or juveniles. Most pulli were ringed between May and August, with some later broods between September and October.

3. The location of the ringing site for those captive-bred Barn Owls that have been recovered shows that the distribution of captive-breeding schemes are generally concentrated in Staffordshire/Derbyshire, Devon, Buckinghamshire/Oxfordshire, North Yorkshire, Sussex and Gloucestershire/Gwent.

4. Birds were recovered in a wide range of circumstances. Road casualties were the most common cause of finding circumstances and accounted for 40% of all recoveries, although it should be noted that birds dying away from roads or human sites are less likely to be found.

5. Of the 135 birds recovered, over half were found within 0-10 km of the ringing site, which is a similar pattern to wild birds in their first year of life. The maximum distance recorded was 262 km.

6. Of the birds that have recovered, 70% were found within the first six months after ringing, and 90% were found within a year of ringing.

7. We recommend that:

a) information gathered by the Barn Owl Release Scheme Monitoring Project is analysed with that from the national ringing scheme to compare the survival rates of captive-bred and wild Barn Owls;
b) a preliminary assessment be made of the factors affecting the success of different release methodologies; and that
c) it is important the Barn Owl Release Scheme Monitoring is continued to enable a full evaluation of the release of captive-bred Barn Owls in the future.

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