Breeding

Black-capped Petrel breeds in loose colonies, with nesting habitat found in both montane broadleaf and pine forests. All currently described petrel nests occur in areas with both soil and vegetation present. The species nests in mountain ranges composed primarily of dolomitic limestone. The female lays a single egg at the end of a burrow that both members of a pair help to construct. Both adults share in incubation, brooding, and feeding duties

In the dark form, breeding occurs between November and August. Nest initiation begins in November. Petrels lay eggs in mid- to late January. Chicks hatch from mid- to late March and fledge from mid-June to as late as early August (see Figure 1).

The timing of breeding appears to be different for the light-form (7 Howell, S. N. G., and J. B. Patteson (2008). Variation in the Black-capped Petrel – one species or more? Alula 14(2):70–83. Close , 12 Satgé, Y. G., B. S. Keitt, C. P. Gaskin, J. B. Patteson, and P. G. R. Jodice (2023). Spatial segregation between phenotypes of the diablotin black-capped petrel Pterodroma hasitata during the non-breeding period. Endangered Species Research 51:183-201. Close ), with nest initiation beginning as early as October and egg-laying beginning in December. Fledging occurs in April (E. Rupp, unpublished data).

Microhabitat

The species nests in rock crevices, dirt burrows, or burrows dug into pine needles. Burrow depths are between 0.5–3.0 m (Ernst Rupp, personal communication).

Site Characteristics

On Hispaniola, petrel nests are found between 15–25 km from the sea at elevations between 1,500–2,300 meters above sea level (67 Satgé, Y. G., E. Rupp, A. Brown, and P. G. R. Jodice (2020). Habitat modelling locates nesting areas of the Endangered Black-capped Petrel Pterodroma hasitata on Hispaniola and identifies habitat loss. Bird Conservation International 31:573-590 Close ). Nests may occur on flat, moderately steep, or extremely steep slopes, and can be found on north, south, east, and west facing slopes. Of the nests that have been identified, some are alone and 100-200 m away from the nearest nest (Loma Quemada); others are in loose clusters of 3 to 10 nests, grouped within a 20-50m radius (La Visite, Loma del Toro, Valle Nuevo; Anderson Jean, personal communication; Ernst Rupp, personal communication). Within a nesting area, clusters may be 100-200m away from each other (2 Wheeler, J., Y. Satgé, A. Brown, J. Goetz, B. Keitt, H. Nevins, and E. Rupp (2021). Black-capped Petrel Conservation Update and Action Plan: Conserving the Diablotin. International Black-capped Petrel Conservation Group. Close ).

Construction Process

Structure and Composition

Nest cups are often lined with leaf litter, pine needles, or feathers, but are also occasionally devoid of introduced materials (Ernst Rupp, personal communication).

Dimensions

Microclimate

Maintenance or Reuse of Nests

Shape

Rounded-ovate.

Size

The average dimensions of 6 failed eggs collected in the Dominican Republic in 2018 were as follows: length 62.6 mm (55.9–66.3 mm ­± 3.4 SD); breadth 46.2 mm (45.5–47.6 mm ± 0.7 SD) (YGS, unpublished data).

Eggshell Thickness

From 6 failed eggs collected in the Dominican Republic: 0.4 mm (0.3–0.5 mm ± 0.0 SD) (YGS, unpublished data).

Color and Surface Texture

White.

Clutch Size

Females lay a single egg.

Information needed.

Information needed.

Limited information exists on the early life of chicks. Camera trap information suggests that until 2–3 weeks old, chicks are guarded by an adult at all times. Later, chicks are left on their own while parents are foraging. Starting at 2.5–3 months old, chicks come out of the burrow at night to preen, stretch, and practice flapping (E. Rupp, personal communication).

Information needed.

Chicks fledge at 3.5 months of age (Ernst Rupp, personal communication).

Not reported; as in other Pterodroma, immatures are expected to remain at sea until they reach sexual maturity (expected to be at 3-5 years of age).