11 research outputs found
Temperature but not rainfall influences timing of breeding in a desert bird, the trumpeter finch (Bucanetes githagineus)
Reproductive performance in birds depends on
several factors, one of the most important being the time
of breeding. Birds try to fit offspring birth and growth to
peak vegetative production in order to assure fledgling
survival. In arid environments, where weather conditions
are often extreme, birds must face unpredictable abiotic
conditions. This study uses a border population of the
trumpeter finch (Bucanetes githagineus) as a model to test
whether climate variables (rainfall and temperature)
influence breeding parameters by comparing 2 years with
very different weather. The study was carried out in the
Tabernas desert (southeastern Spain) in 2004 and 2005. A
comparison of laying dates in the 2 years shows a 40-day
delay in the date of the first clutch in the coldest year
(mean minimum temperature 3 C lower in 2005 than in
2004). However, once the breeding season started, the
number of clutches, clutch size, duration of the incubation
period, nestling phase, fledgling rates and productivity
were similar. One likely explanation for this delay is that
low temperatures did not allow the germination of
Diplotaxis sp., a plant forming the bulk of the trumpeter
finch diet during spring. Its absence could prevent onset of
breeding, although other temperature-related factors could
also be involved. Although rainfall has frequently been
reported as a limiting factor for arid bird species, our
2-year study shows that temperature can also influence the
breeding biology of arid bird species, by affecting its
timing.This work was supported
by Spanish Ministry of Education and Science projects REN 2002-
00169 and CGL2005-01771/BOS. Permits for the field work in Coto
Las Lomillas (Tabernas desert) were granted by A. Juarez.Peer reviewe