TY - JOUR
T1 - A scarcity of females may constrain population growth of threatened bird species
T2 - Case notes from the Critically Endangered Raso Lark Alauda razae
AU - De Brooke, M. D L
AU - Flower, T. P.
AU - Mainwaring, M. C.
PY - 2010/12
Y1 - 2010/12
N2 - Donald (2007) showed that the adult sex ratios of wild bird populations tended to be male-biased, and that this bias was stronger in threatened species than in those of least concern. Here we show that, in 2004, the world population of the Critically Endangered Raso Lark was 65 individuals, 70% of which were male (adult sex ratio 0.70). In 2008, the population numbered approximately 175 (including juveniles) and the adult sex ratio was 0.58. Both ratios were significantly different from parity. All adult females were observed to be both paired and holding a territory. The observations therefore support Donald's (2007) suggestion that a shortage of females can be an important constraint on the growth of threatened bird populations, a constraint that needs attention in conservation planning.
AB - Donald (2007) showed that the adult sex ratios of wild bird populations tended to be male-biased, and that this bias was stronger in threatened species than in those of least concern. Here we show that, in 2004, the world population of the Critically Endangered Raso Lark was 65 individuals, 70% of which were male (adult sex ratio 0.70). In 2008, the population numbered approximately 175 (including juveniles) and the adult sex ratio was 0.58. Both ratios were significantly different from parity. All adult females were observed to be both paired and holding a territory. The observations therefore support Donald's (2007) suggestion that a shortage of females can be an important constraint on the growth of threatened bird populations, a constraint that needs attention in conservation planning.
UR - http://www.scopus.com/inward/record.url?scp=79952988394&partnerID=8YFLogxK
U2 - 10.1017/S0959270910000225
DO - 10.1017/S0959270910000225
M3 - Article
AN - SCOPUS:79952988394
SN - 0959-2709
VL - 20
SP - 382
EP - 384
JO - Bird Conservation International
JF - Bird Conservation International
IS - 4
ER -