Aves da Pátria da Leari - Sociedade Brasileira de Ornitologia

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Todirostrum cinereum cearae (Cory, 1916)
Commom Tody-Flycatcher
Aves da Pátria da Leari
During the study period between December and March, we managed to locate 23 nests of this species and
collect data from 22 of them. One of the nests was 8 cms from the ground and attached to a branch of the
Pitecelobium sp tree and was the only one that was not systematically accompanied nor manipulated to gauge
the morpho-metric data fr the eggs or chicks. Cherie (1890) presented data about nests that she accompanied
in Costa Rica. Skutch (1930) found nests between the months of March and June in Panama. Haverschimidt
(1978) accompanied nests from July to August in Suriname. Richmond and Skutch (1930) report of nests with
eggs in March in Nicaragua, and Carriker apud Skutch (1930) registered nests between April and July in Costa
Rica. Cruz & Andrews registered the occurrence of 52 nests in Venezuela from May to October, with a peak
in June (N=26) and August (N=15).
As Skutch, (1960) relates, the construction of nests in the area of Cetrel by 20 pairs was undertaken by two
individuals, the building activity of each member of the pair happened when the male was present and the
female absent or vice-versa and sometimes simultaneously when both were present in the nest, manipulating
material (see photos 7, 8, 9, 10 and 11). Another scene we witnessed was of both the pair on top of the nest
but only one working on the building part.
The building period for the outer part of the nest of a pair who had had its nest invaded by a predator was 28
days. After that the pair started to finish the inner chamber of the nest. Skutch (1930), in his presentation of
nest data collected in Panama, said that the construction of the inner chamber had taken the most time.
The building of another complete nest in the grounds of Cetrel took 32 days. During this period, a ruddy
ground dove (Columbina talpacoti) constructed its nest, incubated and then looked after five chicks. The T.
cinereum expends a considerable amount of time during reproduction principally consumed in the construction
of its nest. According to Skutch (1960), the average time it takes to construct this specie’s nest in Central
America is between four or five weeks, although some pairs can take less time, often when the building takes
place in an abandoned nest that has been a victimized by predators.
Of the 23 nests that were found, 15 were completely exposed to the sun during the entire day and eight nests
were protected by the vegetation. In terms of proximity to water within a 100-meter radius, seven were within
this band (three actually on a surface of water) while 16 were outside this radius.
Of all the nests found, 20 were accompanied until a predator targeted them or until the chicks fledged. Of
these in two of them (10%) the adults attained success, 12 (60%) were victims of predators, five nests were
abandoned and one was found on the ground. Among all the nests that were victims of predators, in six of
them (50%), the eggs disappeared, in five (41.7%) the nests had been completed but no eggs laid, and one
was still under construction. With the exception of this one, all the nests considered to have been victims of
predators showed signs of modification in their shape, principally the external part. This suggest some sort
of manipulation by mammals. The mammals who are potential predators in this region include: the tuftedear
marmoset (Callithrix jacchus), the common opossum (Didelphis albiventer) and other smaller marsupials
from the Marmosa sp, in addition to other small rodents. We suspect that the squirrel cuckoo (Piaya cayana) is
also a predator of eggs from the species. Another possibility for agents of nest modification is the presence of
piling birds, such as the greater kiskadee (Pitangus sulphuratus) It’s possible that the only nest with eggs but