On 9 March 2013, two adult females with brood patches
chlorurus adults are sexually monomorphic in plumage, each adult with a brood patch was classified as female; this is based partly on the fact that in other towhees, only females have brood patches
and brood the young (Ehrlich et al.
Even more important may be the fact that jaegers only have two brood patches
, whereas most gull species that often incubate three eggs, have three brood patches
In support of this hypothesis, male Chuck-will's-widows do not have brood patches
The field and museum work we report here was planned to evaluate assumptions about the status of brood patches
and the June abundance of these three species in coastal Sinaloa in June.
We recorded brood patches
for 241 individuals (252 captures) during this period.
Only males were expected to be attracted by playback of calls but five individuals captured had brood patches
and were probably females.
However, only 15 females had well-developed brood patches
and two males had cloacal protuberances and a partially developed brood patch.
The remaining two Wood Thrush females had no evidence of ovum formation in the oviduct nor had fully vascularized brood patches
, indicating they were not incubating eggs.
We captured birds weekly and recorded molt, and presence of brood patches
and cloacal protuberances as indicators of reproduction.
Both adults had brood patches
and were involved in incubation (14/14 nests), brooding (16/16 nests), and feeding nestlings at day 2-3 (16/16 nests), day 7-8 (20/20 nests), and day 11-12 (15/15 nests).
Further evidence of this species' nesting phenology is provided by two mist-netted females with fully-developed incubation or brood patches