Data for analysis of variables influencing breeding success in the Canarian houbara

Precipitation is one of the main triggers of reproduction in
desert-breeding birds. The unpredictability of rainfall patterns in arid
environments has led species to adapt their breeding effort to episodes of
abundant food after rainfall. The response is not the same for all
individuals in a population, and may vary especially with the age and
experience of each female. Here we investigate the effects of
precipitation, temperature, body size and breeding experience, among other
variables, on reproductive parameters of 20 females of Canarian houbara
bustard (Chlamydotis undulata fuertaventurae), an endangered desert bird
endemic of the eastern Canary Islands. Precipitation and breeding
experience were the main determinants of female breeding performance.
Higher rainfall determined an increase in nesting rate, and earlier autumn
rains caused an advancement of nesting to October, allowing the breeding
season to be extended to eight months. This favoured an extraordinary
increase in productivity in more rainy breeding seasons, with 15 times
more females nesting in the two most rainy winters than in dry years. In
addition, females with more breeding experience showed a higher tendency
to breed, higher nest attempt and fledging success, and longer breeding
season, which allowed them to rear more chicks. A female even double
brooded successfully in the same season, which, considering that chicks
remain with the mother for up to six months, indicates a great capacity to
optimise reproductive investment, by adapting to highly variable rainfall
regimes. In recent decades, the eastern Canary Islands have undergone a
process of aridification, and climate models predict a medium-term
increase in the frequency and duration of drought periods. Thus, Canarian
houbaras are particularly vulnerable to climate change, so measures are
urgently needed to reduce their mortality and improve the quality of their
habitat, in order to favour their reproduction and prevent their
extinction.