Tumbes Swallow - Reproduction

Reproduction

The first nest of Tumbes Swallow was reported by Robbins et al. (1997). More extensive data, on which the following account is based, is from research teams from Cornell University and the Golondrinas de las Americas project in 2010-2011; data from this project are consistent with the initial. more limited observations by Robbins et al. (1997). The Golondrinas study site for Tumbes Swallow is the Santuario Historical Bosque de Pomac, Lambayeque Peru. At this site, in the season of study (4 Dec 2010-10 May 2011), a La Niña event occurred, causing severe drought conditions and little rainfall. As such, future study may reveal very different data.

Tumbes Swallow, like other Tachycineta, nests in cavities. The nest reported by Robbins et al. 1997) was in a tree cavity, suspected to have been excavated originally by a woodpecker, and was ca 2 m above the ground. Tumbes Swallow also will occupy artificial nest boxes. Out of 49 artificial nest boxes at Pomac, 37 nests were observed (Stager et al 2012). Nests were built in nest boxes put on the site in 2009 that were wired to trees approximately 2 m off the ground. Boxes appeared to be resused and new materials layered over existing materials. All boxes were cleared out upon arrival at field site (December 2010). Of the ten natural nests discovered, host trees of the genus Proposis were favored by the swallows. Found breeding in Santuario Historico Bosque de Pomac from mid-December through late April (Stager et al. 2012).

Nests consisited largely of feathers (mean = 367 ± 23.5 feathers, n = 16 nests) and included a shallow, circular cup. Feathers that could be identified came from Long-tailed Mockingbird (Mimus longicaudatus), West Peruvian Dove (Zenaida meloda), Variable Hawk (Buteo polyosoma), Pacific Parrotlet (Forpus coelestis), Tropical Kingbird (Tyrannus melancholicus), Cattle Egret (Bubulcus ibis), "Pacific Hornero" (Furnarius leucopus cinnamomeus), Lesser Nighthawk (Chordeiles acutipennis) and domestic Muscovy (Cairina moschata). Most of the remaining nesting material was dried grasses (which is hard to find in the area), though other materials included dried leaves, bark, fur, plastic bags, black plastic, tissue, nylon string, seed casings, Capparis inflorescences, and reptile skin.

Clutch initiation date ranged from December 1 to April 23. These consisted of 18 first attempts, 15 second attempts, 3 third attempts, and 1 fourth attempt.

Mean clutch size was 2.68 ± 0.10 and did not differ significantly between first (n = 18; mean = 2.61 ± 0.14) and second nesting attempts (n = 15; mean = 2.67 ± 0.16), though it did increase significantly for third clutches (n = 3; mean = 3.00 ± 0, t = 2.7, df = 17, P = 0.01). The incubation period was between 15 and 18 days with a mean of 16.11 ± 0.14 days, excluding six nests for which the clutch completion date could not be determined accurately (± 2 days). For the 37 nesting attempts followed to hatch, egg survival was 84.38%. No predation of eggs was recorded; egg loss was chiefly caused by abandonment.

Hatching success was 92.11 %, excluding three clutches associated with a predation event shortly after hatch before the hatching success of the entire clutch could truly be deduced. In nests persisting until hatching (n = 29 clutches, excluding the three aforementioned clutches), four clutches contained one egg and one clutch contained two eggs that did not hatch.

The nestling period ranged from 26 to 32 days (n = 15 nests, excluding one nest for which fledge could not be ascertained with sufficient certainty (± 4 days)). Thirty-six nestlings fledged from 16 nests with a success rate of 50.0% (mean = 1.20 ± 0.23 nestlings per brood, n = 30). Nine of 18 first nesting attempts successfully fledged offspring. Of these, seven pairs attempted second broods, three of which also successfully fledged. Of the eight additional second attempts (replacement clutches), three fledged successfully. Two of the three third attempts successfully fledged offspring, though neither pair was successful in either of its first two attempts. The sole fourth nesting attempt came from a pair that was successful in its first attempt but failed in both the second and third attempts. Our field crews left before the fate of this fourth attempt could be determined.

The period between a new clutch initiation following an unsuccessful nesting attempt ranged from 10–19 days (mean = 15.4 ± 1.2; n = 10). The period between a new clutch initiation following a successfully fledged brood ranged from 7–47 days (mean = 23.5 ± 4.48; n = 8). However, fledglings were not monitored after leaving the nest so it is not known whether they were successful as juveniles or the degree of post-fledging parental care exhibited (Stager et al. 2012).