The sooty falcon is a high conservation priority species (considered regionally vulnerable), so it is crucial to understand how the population is doing during different stages of its life cycle. Different breeding parameters can indicate at which stage the population is more vulnerable and identify any threats that need to be addressed. Assessment of sooty falcon breeding success was done in September to October, by recording not only the number of nests, but also the number of eggs per nest, the number that hatched, and the number of checks successfully fledged (i.e., survived through the breeding season and departed with other falcons to their winterfeeding area in Madagascar). Breeding outcomes were assessed by visual inspection in periodic visits to the nest to check the status of eggs or chicks in nests. The team is testing the use of cameras systems that would be able to remotely gather information on the timing and cause of any egg or chick failures while minimizing any potential disturbance
Results: Life Cycle, Abundance & Distribution • Nearly 25,000 breeding pairs belonging to 14 species recorded, breeding birds were found on 75 islands, and colonies on 57 islands • The most abundant and widespread species was the white-cheeked tern, with 11,758 breeding pairs present on 47 islands. The osprey was equally widespread, but with only 71 breeding pairs in total. The lesser-crested tern had the highest colony density, with 4,453 breeding pairs on 10 islands. • 41 breeding pairs of sooty falcons were recorded in 2021, about 2-3 percent of the estimated global population. The island of Quman alone had 20 breeding pairs. • Timing of breeding cycle was identified for all species: the pre-breeding phase (breeding pairs inspect the area and build nests); the incubation phase (adults incubating eggs); and the chickrearing phase, that lasts from the hatching to the fledging of the chicks. A species is most susceptible to disturbance during incubation and chick-rearing phases, while disturbance during the pre-breeding phase can lead to the abandonment of the breeding site completely.
Red-billed tropicbird with chick in nest.
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