The Nest and Eggs of Rusty-Fronted Tody-Flycatcher Poecilotriccus Latirostris

Cotinga 36 Short Communications The nest and eggs of Rusty- m from the nest and returned It contained two eggs, similar in fronted Tody-Flycatcher three hours later. A review of the appearance to those in the first Poecilotriccus latirostris video revealed that no adult had nest, but which were completely The genus Poecilotriccus comprises visited the nest during this period. empty and whose shells crumbled 12 species11 of small, stout-bodied The following evening, at 17h45, on touching them, indicating they flycatchers that generally forage I flushed an adult from the nest, had been abandoned some time inconspicuously in the dense, which paused long enough for me ago. Pairs of P. latirostris were tangled undergrowth of humid to identify it, before disappearing generally uncommon in this area, forest edges3,13. Rusty-fronted silently from view. I was unable and the small distance between Tody-Flycatcher P. latirostris to closely monitor the nest, but the two nests strongly suggests inhabits forest edges and second returned on 3 March. At 06h45 the they belonged to the same pair. growth, especially along rivers nest was again unattended and Both nests were pyriform balls and on river islands, at elevations the eggs were cold to the touch. with a slightly hooded entrance below 1,100 m along the eastern Both, however, showed early in their lower third, but central base of the Andes from east-central embryonic development when held to the spherical egg chamber Colombia to north-west Bolivia, up to the light. Video surveillance (Fig. 1). Both were suspended as and throughout western of the nest from 06h45 to 08h00 to be isolated from surrounding Brazilian Amazonia3. Of the revealed no adult activity. On 6 vegetation within small openings seven recognised subspecies3, P. March, at 13h30 the eggs were in the understorey. One was l. caniceps occurs from south-east again cold and showed no further attached to the drooping tip of a Colombia and north-west Brazil, development. Both adults were small shrub and the other to the south to eastern Peru. In eastern foraging in the area of the nest but tip of a thin vine, 1.5 m and 2.4 Ecuador it is rare above 700 m12 showed no signs of alarm at my m above ground, respectively. and, though inconspicuous, I presence. On 10 March I carefully They were composed almost have found it locally common in approached the nest at 21h40, well entirely of strips of Gynerium Gynerium cane and second growth after dark. There was no adult grass, loosely bound with a few on islands and at edges of larger on the nest and the eggs were rootlets and flexible pale grass rivers. Like most of its congeners, cold and showed no additional fibres. Thinner leaf strips and the nesting biology of P. latirostris development, indicating the nest fibres were used to form a poorly is completely undocumented. had been abandoned. During my differentiated lining to the lower Here I describe two nests and initial visit on 26 February, only part of the egg chamber. Broader two clutches of P. l. caniceps from c.10 m from the first nest, I found strips were twisted around the eastern Ecuador. a second, nearly identical nest. supporting vine above the nest On 26 February 2013 I found two nests of P. l. caniceps on the banks of the Napo River (01°01’57.4”S 77°35’11.7”W), near Ahuano, prov. Napo, at 375 m. This area of the river edge is rocky and flat, prone to periodic water inundation annually and affected by massive flooding every few years. The several isolated patches of second growth on the floodplain are characterised by dense stands of Gynerium, 3–5 m tall, with only a few trees (predominantly Inga and Cecropia) emerging above the grass. The ‘understorey’ comprised tangles of herbaceous vines and small, shrubby legumes (cf. Calliandra). Both nests described below were c.150 m from the main course of the river, separated by a near-treeless expanse of sand and rocks that occasionally floods for several days at a time (mostly in May–July). At 08h15 I discovered an Figure 1. Two nests of Rusty-fronted Tody-flycatcher Poecilotriccus latirostris, unattended nest with two cold, near Ahuano, prov. Napo, Ecuador, 28 February 2013; the nest on the left was completely undeveloped eggs. I found with two freshly laid eggs, while that on the right contained two recently placed a camera on a tripod c.5 abandoned eggs (Harold F. Greeney) 59 Cotinga 36 Short Communications chamber, drooping down to cover somewhat from those of the three the nest and forming the upward congeners, all of which lay white ‘tail’ that gave the nests their eggs with comparatively course teardrop shape. Measurements and sparse cinnamon flecking and (cm) for the first and second nests spotting, generally forming a ring were, respectively: total external at the larger end. Sample sizes, height excluding material hanging however, are still quite small, below the nest 26 and 20; external and further descriptions will be height of the nest chamber 11.0 necessary to evaluate the degree of and 11.5; external diameter of the variation both within and between nest chamber 9 and 9; external Poecilotriccus species. depth (front to back) of the nest chamber 7.0 and 7.5; length of Acknowledgements material hanging below the nest I thank Field Guides Inc., John V. in a loose ‘tail’ 5 and 8 (both had & the late Ruth Ann Moore, Matt a few pieces hanging as low as Kaplan, Margy Green, the PBNHS, 10–15 cm); entrance diameter 3 Population Biology Foundation, and 3; entrance height 2.0 and 2.5; and Tom Walla for supporting my extension of entrance hood from field work. Demis Bucci and Marco the nest 2.0 and 2.5; internal nest Aurelio Crozariol improved earlier chamber diameter 4.0 and 4.5; Figure 2. Eggs of Rusty-fronted drafts with helpful comments. internal egg cup depth 3.5 and Tody-flycatcher Poecilotriccus latirostris, 4.0; internal height of the nest References near Ahuano, prov. Napo, Ecuador, 28 1. Dobbs, R. C. & Greeney, chamber (including cup depth) 8.0 February 2013 (Harold F. Greeney and 8.5. All four eggs were white H. F. (2006) Nesting and with dense, very fine cinnamon foraging ecology of the flecking, relatively evenly nest found under construction at Rufous-breasted Flycatcher distributed (Fig. 2). I was only able Inocência, Mato Grosso do Sul, (Leptopogon rufipectus). Orn. to measure and weigh eggs from Brazil, on 28 February 2009, by Neotrop. 17: 173–181. the first nest, on 26 February, D. Bucci (www.wikiaves.com.br/ 2. Dyrcz, A. & Greeney, H. F. before they showed any signs of fotogrande.php?f=108141&g=1). (2010) Breeding ecology of development. They measured That nest (belonging to P. l. the Smoke-colored Pewee 16.3 × 11.3 mm and 16.9 × 11.8 ochropterus) appears near-identical (Contopus fumigatus) in mm, and weighed 1.1 g and 1.3 g, to those described here. Gilliard4 northeastern Ecuador. Orn. respectively. provided a cursory description of Neotrop. 21: 489–495. It is unclear why both nests unoccupied nests he presumed to 3. Fitzpatrick, J. W. (2004) were abandoned with eggs. That belong to Ruddy Tody-Flycatcher Family Tyrannidae (tyrant- the eggs at the second nest were P. russatus. Although he was flycatchers). In: del Hoyo, J., intact but empty suggests that probably correct, the nests Elliott, A. & Christie, D. A. they were abandoned early in and eggs of only four other (eds.) Handbook of the birds development. Eggs at the first nest Poecilotriccus have been properly of the world, 9. Barcelona: were abandoned while I was not described. The nests of Slate- Lynx Edicions. in the area, so my presence was headed Tody-Flycatcher P. sylvia, 4. Gilliard, E. T. (1941) The unlikely to have been the cause. of Central and northern South birds of Mt. Auyán-tepui, Most tyrannids in north-east America, and those of Ochre-faced Venezuela. Bull. Amer. Mus. Ecuador breed mainly during Tody-Flycatcher P. plumbeiceps Nat. Hist. 77: 439–508. the drier months (September– of southern South America are 5. Greeney, H. F. & Dyrcz, A. January)1,2,5,6, including the relatively well known8,10,14–15. Nests (2011) Breeding biology congeneric Rufous-crowned of P. ruficeps have been studied of Pale-edged Flycatcher Myiarchus cephalotes Tody-Flycatcher P. ruficeps7. It is only in north-east Ecuador7, and a ( ) in Orn. probable that these two nests of single partially constructed nest of northeastern Ecuador. Colombiana P. latirostris, found in the early Black-and-white Tody-Flycatcher 11: 49–57. wet season, may have been late P. capitalis was recently described 6. Greeney, H. F., Krabbe, N., re-nesting attempts that were from south-east Ecuador9. The Lysinger, M. & Funk, W. C. abandoned due to unfavourable nests of all these species are very (2004) Observations on the conditions. I predict that further similar to those of P. latirostris, breeding and vocalizations of observations will reveal that P. both in form and placement, and the Fulvous-breasted Flatbill Rhynchocyclus fulvipectus latirostris is also a dry-season all four species appear to favour ( ) Orn. breeder in the region. long, thin strips of dead material in eastern Ecuador. Neotrop The only previous data (e.g. grass) to construct the bulk of . 15: 365–370. concerning nesting of Rusty- the nest. The eggs of P. latirostris, 7. Greeney, H. F., Dobbs, R. fronted Tody-Flycatcher was a however, appear to differ C., Martin, P.

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