The cause or timing of the three failures was not determined as climbing to the nest is not undertaken during incubation. One of these nests failed for the second successive year.
Of the successful nests, three nests contained one chick, 12 nests two chicks and 6 nests three chicks. Three infertile eggs were taken for analysis. Most of the young were tagged with a white tag on the left wing and red tag on the right, although three fledged before tags could be fitted. Radio transmitters were fitted to three nestlings prior to fledging. A larger increase in the population was expected this year and it is possible that some nests in the area were not found. It will be interesting to see how many untagged juveniles are seen at communal roost sites over the winter, which will give an indication as to the number of nests missed.
A small number of birds were lost as a result of poisoning in the 2003 breeding season. These included an adult killed by an illegal poison bait and several birds, including at least two nestlings, killed by ingesting rat poison in their food.
Two nests were located by radio tracking, fledging two young each. Black P , a four year old male, and Blue S, a two year old female. She had recently returned from the Chilterns where Peter Stevens had been monitoring her.
