The first nest described was found in the Sierra de Bahorucos 2 April 1974 (Kepler et al. 1975). The nest is an open cup similar to a White-winged Crossbill nest, and is constructed of small twigs and needles from P. occidentalis and lined with green pine needles and lichens. For two nests observed in 1998, inside dimensions measured 6.5 and 4.6 cm deep, and 5.8 and 7.0 cm wide (Latta et al. 2002).
Nests are generally located high in pine trees (mean nest height of 14.2 ± 0.81 m) and near the trunk (1.27 ± 0.29 m from trunk). Nest trees average 17.5 ± 0.9 m tall with 121.0 ± 31.4 cones. Nest trees occur in groups with similar-sized trees but are distinguished by having more cones (Latta et al. 2000). Latta et al. (2000) distinguished nesting from non-nesting sites at local and landscape levels. At the local level, nests are predicted 78% of the time by stem count and mean canopy cover. The number of broadleaf trees >3 cm dbh, fragmentation, mean canopy height, and mean canopy cover predicted nesting habitat at the landscape level 90% of time.
Hispaniolan Crossbills tend to nest in clusters, similar to White-winged Crossbills in North America. Possible explanations for clumped nesting include exploitation of a favorable microclimate, food availability, and/or predator defense (Latta et al. 2000).
Nests are constructed only by the female (Latta et al. 2002). At one nest observed under construction in the Sierra de Bahoruco, the female made an average of 6.5 trips/h to the nest. She searched for nesting materials ~25 m from the nest site. The male guards the female and nest during construction, with construction lasting one week.
Most nesting occurs in late winter to early spring, but breeding may take place year-round if cones are available (as observed in other crossbill species). Nests have been found from early January to April; however, juveniles have been reported as early as the end of January and as late as November, which suggests nesting into August (Latta et al. 2000).
Clutch size ranges from 2-3 eggs, but data are limited. Eggs are smooth, variable in color, with a white or pale blue base color and small brownish markings on the larger end (Latta et al. 2002).
Information on incubation is from one nest (Latta et al. 2002). The female incubated for 13 days and received food from her mate at a mean interval of 1.3 h. The female took frequent, short breaks to search for food near the nest. The male did not appear to guard the nest during the female’s absence and was only detected when feeding the female.
Latta et al. (2002) observed brooding behavior at two nests. Young are altricial; they are born naked, with eyes closed, a pinkish gray bill, and a purplish-pink gape. Nestlings begin to develop down two days after hatching and are covered in light gray down on the third day. As noted elsewhere, the young are fed mostly pine seeds (80-90%) and Hemiptera parts of a single, unidentified species (10-20%). Chicks are brooded solely by the female and may be left alone for significant periods of time while the female forages (mean time unattended = 49.4 min). Young are fed regurgitated boluses from both parents with the majority of feedings given by the female (82.4% of observations). The mean time between feeding bouts is 24.0 min. The male provides food to nestlings (1.8 h intervals) and to the female (2.8 h intervals), and will occasionally remain at the nest after feeding the female to attend the chicks while the female forages. Females return to the nest after a mean of 58.2 min. Both sexes consume fecal sacs (Latta et al. 2002).
Length of nestling and post-fledging period are unknown. Juveniles continue to be fed by the parents after fledging (Latta et al. 2002).