Action: Translocate pelicans
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Two reviews of a brown pelican Pelecanus occidentalis translocation programme in the USA found high survival of translocated nestlings and that the target population grew enormously, to over 16,000 nests. The authors note that some of the growth may have been due to immigration from the source populations.
Supporting evidence from individual studies
A review of a 1968-76 brown pelican Pelecanus occidentalis translocation programme between six colonies in Florida and three coastal sites in Louisiana, USA (Nesbitt et al. 1978), found that 98% of 778 nestlings (eight to 11 weeks old) moved survived the journey and were successfully released, although all birds released at one site in 1968-9 died, meaning that all subsequent releases were at a single site. The first breeding in Louisiana was recorded in 1971, when the oldest released birds were three years old, and between 1971 and 1976 a total of 221 young fledged successfully. In 1975, an estimated 35–40% of the standing population of 400–450 pelicans died, probably as a consequence of contamination by endrin (an organochloride pesticide). Birds were provided with food twice daily after release.
A 2003 review (Holm et al. 2003) of the same translocation programme as in Nesbitt et al. 1978, found that between 1968 and 1980, a total of 1,276 pelican nestlings were translocated and that the population increased exponentially from 1971 until 1999, with a peak of 16,405 nests across seven colonies in 2001 (a peak of eleven colonies was reached in 2000). Nests produced an average of 1.7 nestlings between 1971 and 2001 (with a peak of 2.1 nestlings/nest in 2001), which, combined with pelicans’ long lifespans and a decline in the number of birds in Florida, leads the authors to suggest that the exponential growth of the Louisiana population may have been partly due to immigration from nearby states.
- Nesbitt S.A., Williams L.E. Jr., McNease L. & Joanen T. (1978) Brown pelican restocking efforts in Louisiana. Wilson Bulletin, 90, 443-445
- Holm G.O. Jr., Hess T.J. Jr., Justic D., McNease L., Linscombe R.G. & Nesbitt S.A. (2003) Population recovery of the eastern brown pelican following its extirpation in Louisiana. Wilson Bulletin, 115, 431-437