Connie Campbell photos Crossville, Al
Yellow Finch
Life History
Food
Although no systematic study of the Yellow-thighed Finch's diet has been undertaken, it is a generalist and opportunistic frugivore, nectarivore and insectivore. Leck and Hilty (1968) found mist-netted birds stained by small (5 mm diameter) blue berries from a fruiting patch of Leandra subseriata (Melastomataceae) in western Panama. Murray (1968) observed the finch feeding on Witheringia solanacea and W. coccoloboides (Solanaeceae) fruits, and ingesting 71% of the former´s seeds and none of the latter’s. Berries may be mandibulated, without their seeds being ingested. Seeds that are ingested were ground up in the gut (only 2 out of 95 seeds were voided intact). Nectar-feeding also is documented, as the finch pinches corollas of tubular flowers (e.g. Jacobinia aurea, Salvia nervata) to squeeze out the nectar (Skutch 1967, Fisk and Steen 1976). The finch was observed feeding on Müllerian bodies (proteinaceous capsules produced by many ant-associated tree species) it had picked from the petioles of Cecropia leaves (Skutch 1967). Its diet also includes spiders and insects, plucked from within bromeliads and off the ground (Skutch 1967).
Yellow-thighed Finch is a resourceful omnivore and its "diversified foraging parallels its variety of habitats"(Slud 1964).
Behavior
Yellow-thighed Finch is gregarious, and frequently interacts with its group members.
Slud (1964) likens its habits to those of an ani (Crotophaga), describing its actions as "awkward" and "windblown". Its rapid movements and frequent tail-flicking make for an energetic impression. Greenlaw (1977) reports that bill-sweeping is a commonly used foraging behavior by Yellow-thighed Finch, and that bilateral scratching ("hop-scratching" or "double-scratching") is unknown. However, Slud (1964) describes its likeness to the hopping foraging-style of Atlapetes, which likely has at least some bilaterally scratching species (Greenlaw 1977). It unlikely to use bilateral scratching as its principal behavior to procure food items, owing to its dietary diversity.
Murray (1968) notes that this finch mashes most fruits before swallowing them, thus eliminating many seeds. Small seeds (Witheringia solanacea, diameter 1.5 mm) were ingested, while large seeds (W. coccoloboides, diameter 2.4 mm) remain in the discarded fruit skin.
Territoriality
Little is known of territoriality in Yellow-thighed Finch, but it appears to at least not hold feeding territories , as the finches mostly travel in loose, large bands (Slud 1964, Skutch 1967).
Sexual Behavior
We know little about the mating system of Yellow-thighed Finch, but pairs are observed at nests and singing together (Skutch 1967).
Social and interspecific behavior
Yellow-thighed Finch feeds in pairs and in family-group, and often associates with mixed species flocks containing species such as Common Bush-Tanager Chlorospingus flavopectus, Spangle-cheeked Tanager Tangara dowii, and Chestnut-capped Brush-Finch Arremon brunneinucha (Stiles and Hespenheide 1971). Stiles and Hespenheide (1971) report an adult Yellow-thighed Finch chasing off a male Slaty Finch Haplospiza rustica, as their separate mixed-species flocks crossed paths.
Predation
Little is known about possible predators of the Yellow-thighed Finch.
Reproduction
The breeding season is Costa Rica is March-May (Stiles and Skutch 1989).
The female constructs a small, bulky open cup nest out of dried bamboo leaves, dry grass. The nest is hidden in the understory, 0.5 m-4.6 m off the ground in rough grasses, bamboo or dense and leafy trees and in vegetation-shrouded ravines (Carriker 1910, Skutch 1967). The two eggs are pale bluish (Carriker 1910) or white with a pale blue wash and are "speckled with brown all over" with a "crown of mingled brown and lilac speckles on the thicker end" (Skutch 1967). They measure on average 24.8 x 18.2 mm (n = 4; Skutch 1967).
Skutch observed a female constructing a nest, and an accompanying male that followed her but did not contribute nesting material, only singing upon reuniting with the female after short absences. The male's role in territory holding (and nestling care) appears to be minimal. Skutch also observed this female being rather defiant while on the nest, almost allowing him to touch her before she left the nest. When flushed off a nest of recently-hatched young, this female displayed wing-raising behaviors, 'unconvincingly feigning injury' (Skutch 1967). The incubation period is not known; in one nest, the young fledged at age 12 days (Skutch 1967).
Yellow Finch
Life History
Food
Although no systematic study of the Yellow-thighed Finch's diet has been undertaken, it is a generalist and opportunistic frugivore, nectarivore and insectivore. Leck and Hilty (1968) found mist-netted birds stained by small (5 mm diameter) blue berries from a fruiting patch of Leandra subseriata (Melastomataceae) in western Panama. Murray (1968) observed the finch feeding on Witheringia solanacea and W. coccoloboides (Solanaeceae) fruits, and ingesting 71% of the former´s seeds and none of the latter’s. Berries may be mandibulated, without their seeds being ingested. Seeds that are ingested were ground up in the gut (only 2 out of 95 seeds were voided intact). Nectar-feeding also is documented, as the finch pinches corollas of tubular flowers (e.g. Jacobinia aurea, Salvia nervata) to squeeze out the nectar (Skutch 1967, Fisk and Steen 1976). The finch was observed feeding on Müllerian bodies (proteinaceous capsules produced by many ant-associated tree species) it had picked from the petioles of Cecropia leaves (Skutch 1967). Its diet also includes spiders and insects, plucked from within bromeliads and off the ground (Skutch 1967).
Yellow-thighed Finch is a resourceful omnivore and its "diversified foraging parallels its variety of habitats"(Slud 1964).
Behavior
Yellow-thighed Finch is gregarious, and frequently interacts with its group members.
Slud (1964) likens its habits to those of an ani (Crotophaga), describing its actions as "awkward" and "windblown". Its rapid movements and frequent tail-flicking make for an energetic impression. Greenlaw (1977) reports that bill-sweeping is a commonly used foraging behavior by Yellow-thighed Finch, and that bilateral scratching ("hop-scratching" or "double-scratching") is unknown. However, Slud (1964) describes its likeness to the hopping foraging-style of Atlapetes, which likely has at least some bilaterally scratching species (Greenlaw 1977). It unlikely to use bilateral scratching as its principal behavior to procure food items, owing to its dietary diversity.
Murray (1968) notes that this finch mashes most fruits before swallowing them, thus eliminating many seeds. Small seeds (Witheringia solanacea, diameter 1.5 mm) were ingested, while large seeds (W. coccoloboides, diameter 2.4 mm) remain in the discarded fruit skin.
Territoriality
Little is known of territoriality in Yellow-thighed Finch, but it appears to at least not hold feeding territories , as the finches mostly travel in loose, large bands (Slud 1964, Skutch 1967).
Sexual Behavior
We know little about the mating system of Yellow-thighed Finch, but pairs are observed at nests and singing together (Skutch 1967).
Social and interspecific behavior
Yellow-thighed Finch feeds in pairs and in family-group, and often associates with mixed species flocks containing species such as Common Bush-Tanager Chlorospingus flavopectus, Spangle-cheeked Tanager Tangara dowii, and Chestnut-capped Brush-Finch Arremon brunneinucha (Stiles and Hespenheide 1971). Stiles and Hespenheide (1971) report an adult Yellow-thighed Finch chasing off a male Slaty Finch Haplospiza rustica, as their separate mixed-species flocks crossed paths.
Predation
Little is known about possible predators of the Yellow-thighed Finch.
Reproduction
The breeding season is Costa Rica is March-May (Stiles and Skutch 1989).
The female constructs a small, bulky open cup nest out of dried bamboo leaves, dry grass. The nest is hidden in the understory, 0.5 m-4.6 m off the ground in rough grasses, bamboo or dense and leafy trees and in vegetation-shrouded ravines (Carriker 1910, Skutch 1967). The two eggs are pale bluish (Carriker 1910) or white with a pale blue wash and are "speckled with brown all over" with a "crown of mingled brown and lilac speckles on the thicker end" (Skutch 1967). They measure on average 24.8 x 18.2 mm (n = 4; Skutch 1967).
Skutch observed a female constructing a nest, and an accompanying male that followed her but did not contribute nesting material, only singing upon reuniting with the female after short absences. The male's role in territory holding (and nestling care) appears to be minimal. Skutch also observed this female being rather defiant while on the nest, almost allowing him to touch her before she left the nest. When flushed off a nest of recently-hatched young, this female displayed wing-raising behaviors, 'unconvincingly feigning injury' (Skutch 1967). The incubation period is not known; in one nest, the young fledged at age 12 days (Skutch 1967).