Breeding

Only four studies have reported nests of Tawny Antpitta, all pertaining to nominate quitensis in Napo, northeastern Ecuador (Black 1982, Greeney and Martin 2005, Greeney and Harms 2008, Greeney et al. 2011). To date, there are no nests described for either of the other two subspecies, and the information summarized here on the nests, eggs, and nesting behavior of Tawny Antpitta pertains entirely to nominate quitensis.

NEST – Nests are usually built in relatively isolated vegetation on the leeward side of ridges where they are sheltered from wind and weather, usually below 2.5 m above the ground and most frequently near the center of the supporting plant (Greeney and Martin 2005). The nest is an open, bulky cup of moss, mud, and small sticks, usually fairly sparsely lined with pale grass stems (Greeney and Martin 2005). They are fairly deep, providing further protection from inclement weather. Measurements (± SD) of three nests measured by Greeney and Martin (2005): outside width 20 ± 4 cm, outside height 14 ± 2 cm with 0–6 cm of hanging moss, inside cup width 10.6 ± 0.6 cm, cup depth 6.8 ± 0.8 cm.

EGG, LAYING AND INCUBATION – The clutch size of Tawny Antpitta is two; the eggs are blue to blue-green, sub-elliptical, and may be completely unmarked, have a few scattered cinnamon spots, or be patterned with heavier cinnamon and lavender flecks and blotches (Greeney and Martin 2005). Published egg measurements are as follows: mean 30.6 ± 0.3 mm by 24.8 ± 0.8 mm, range 30.3-31.1 mm by 23.0-25.5 mm (n = 8, Greeney and Martin 2005). Eggs are laid roughly 48 hours apart and, at one nest, were both laid in the afternoon (Greeney and Harms 2008). Both sexes participate in incubation (Greeney and Martin 2005, Greeney and Harms 2008) for a duration of 22-23 days (n = 1, Greeney and Harms 2008). Greeney and Harms (2008) reported incubation constancy ranging 44% to 97% during daylight hours, the lower percentage occurring on the day of clutch completion, and slowly increasing as incubation progressed. For nests where incubation is already underway, daily coverage generally averages 82-86% (Greeney and Martin 2005, Greeney and Harms 2008). As reported for other antpittas (Greeney et al. 2008), incubating Tawny Antpitta adults spend a measurable amount of time (ca 3-5% of time on the nest) engaged in behaviors such as preening, egg-rolling, and nest maintainance (Greeney and Harms 2008). Both of the aforementioned studies observed adults leaning into the nest and probing at the nest lining, either with sharp thrusting-movements or with the sewing-machine-like movement described in other passerines (Haftorn 1994, Greeney 2004, Greeney et al. 2008b), including antpittas (Dobbs et al. 2003, Greeney and Gelis 2005). While incubating, adult Tawny Antpitta vocalize frequently (Greeney and Martin 2005, Greeney and Harms 2008), but the function of this remains unstudied.

NESTLING AND PARENTAL CARE – There are no published studies on the nestlings or parental care of Tawny Antpitta.

SEASONALITY – In Colombia, specimens in breeding condition are reported from February (quitensis; Cauca) and August (alticola; Santander) (Hilty and Brown 1986). Fledglings (quitensis) are reported in September in Quindio and March in Huila (Fjeldså and Krabbe 1990). A juvenile female was collected in late December in Boyacá, Colombia (alticola, Olivares 1973), and a juvenile male in June in Cundinamarca (Olivares 1967). Additional reports of juveniles (quitensis) include September in Cauca and Quindio, and March in Huila (Fjeldsa and Krabbe 1990). These authors also indicate the presence of immatures in January in northwest Ecuador, July, October, and November in northeast Ecuador, January in Azuay, Ecuador, and August in Piura, Peru. Previously unpublished reports of birds in immature plumage (see Detailed Description) are presented below in Table 1.