How Does Translocation Affect the Subsequent Distribution of Breeding Pairs in a Population of Pied Flycatchers (Ficedula Hypoleuca)?

Abstract

Translocation of adults from one breeding area to several release areas. Birds released to areas without nestboxes returned more to the capture area more than birds released in other nest box areas. Of the birds that bred before in the capture area 78% of males, and 65% of females returned, while 6% males and 23% females bred in the release area. Of the one year old birds 19% bred in the capture area while 45% bred in the release area. For the birds older than 1year but without breeding experience in the capute area 76% of the males and 18% of the females returned to the capture area, while none of the males and 46% of the females bred in the release area. From the birds that were not born in the study area and did not bred there before, 27% of the males and 5% of the females returned to the capture area, and 24% males and 42% females bred in the release area. The difference between the sexes here is probably an age effect, because the males were probably older at capture than the females.The effect of removal on the number of breeding birds was apparently low: the number of removed birds was about twice the number of breeders, and during the experiment there was no clear indication that the number of breeders dropped as a result of the removal of the 'whole' population. This was more the case for males than for females, but also for females there was apparently replacement of the removed birds. The estimate of non-breeders in the capture area was 22,10 and 12 for males in the different years, and for females 4,0,0 suggesting that females can more easily find a breeding site.