White-throated Ground Dove (Gallicolumba xanthonura) (Paluman apaka)
Order: Columbiformes
Family: Columbidae
Chamorro Name: Paluman apaka
SPECIES OVERVIEW
Description: A sexually dimorphic, robust, short-tailed forest dove.
Adult Male: The forehead, face, chin, throat, and upper breast white, lightly washed with a pale buff. The crown, occiput, sides of head, and nape are rusty to dark brown, the remainder of the upper parts are dark bronze-olive. The feathers of mantle and upper wing coverts are broadly edged with metallic purple-violet, the primaries, under wing coverts and axillaries are brown. The tail, lower breast, under parts, bill and feet are dark brown.
Adult Female: Resembles adult male but smaller and with underparts between “ochraceous- tawny” and “cinnamon brown” in color. Head and neck are darker with more rufous than underparts while the remainder of upper surface resembles underparts but with striking olive green sheen, especially on upper wing-coverts. Primaries are brown but outer webs lighter and the tail is rufous brown with a broad black sub-terminal band. The iris of the female is grey or brown with a grey orbital skin. Although less common, an alternate female plumage resembling the adult male plumage has been documented and is described as follows: breast is light drab tinged with light brown and darkening anteriorly; the crown resembles that of normal female although darker and becoming lighter and grayer on neck and nape; the shoulder and wing- coverts compare favorably with that of adult male although lighter and with yellowish tinge; the back is bronzed olive-green as in normal female but the mantle exhibits a few purplish feathers characteristic of the male; abdomen area is “olive brown” with buffy brown edges to the feathers.
Juvenile/Immature: The immature male resembles the adult male but the head and nape are darker brown; the throat and upper breast may be browner and less white. Young males have more noticeable rufous tips on the feathers than females. The immature female resembles the adult female, but with more rufous coloring; the olive-green sheen on feathers is reduced or absent.
Distribution and Status: The White-throated Ground Dove is known to occur on the islands of Asuncion, Agrihan, Pagan, Alamagan, Guguan, Sarigan, Anatahan, Saipan, Tinian, Agiguan, and Rota in the Mariana archipelago. A population was found on Guam but was extirpated in the 1980's by the brown tree snake (Boiga irregularis; Wiles et al. 2003). The species also occurs on the Micronesian Island of Yap.
Subsequent analysis of data from all island-wide surveys (1982 – current), Rota Bridled white-eye VCP surveys (2002-2005), and BBS surveys (2000-2005) indicate a stable to decreasing trend of the species’ populations on Rota. Analysis of Saipan BBS data indicates a significant increase in ground-dove populations between 1991 and 2010.
Habitat: Ground doves occurs in native, secondary, agricultural, and tangan tangan (Leucaena leucocephala) forests, and in habitat mosaics that include open fields. Craig (1996) reported ground doves more frequently in native forests than disturbed habitats, and Jenkins (1983) found the species absent from savanna, wetland, and coastal strand habitats. Ground doves use a range of forest strata, with most of their time spent in either the canopy (45%) or on the ground (30%; Craig 1996).
Food and Feeding Habits: The species is primarily frugivorous but will consume seeds and some leaves and flowers of a wide variety of plant species. Craig (1996) observed ground doves foraging for seeds and probing leaf litter on the ground and feeding on the fruits of native trees, including papaya (Carica papaya). Although other species of ground doves from the same genus are forest under-story herbivores, the White-throated Ground Dove appears to be a microhabitat generalist (Craig 1996). Stophlet (1946) observed a female ground-dove picking at the underside of a leaf and assumed it was gleaning insects. There are no other references or documentation of ground-doves foraging for or consuming insects. Bender ([in review]) found ground doves to be seed predators after feeding trials of both native and non-native plants were executed on a captive setting on Saipan.
Behavior: The ground dove is secretive, solitary, and seldom found in pairs outside of the breeding season (Drahos 1977). The species is often observed flying high over forest canopy, leading Kibler (1950) to suggest that these long flights may indicate widely separated feeding grounds. Data collected by the CNMI DFW suggest that the species is territorial, often foraging singly on the forest floor and stopping to chase away conspecifics (Villagomez 1987). However, ground doves have been observed in groups of 8-15 on three different islands (Saipan, Aguiguan, and Rota; Villagomez 1987), and they appear to tolerate conspecifics that are greater than 10m away; males that approach other males within that distance are generally chased off (Villagomez 1987). Agonistic behavior was observed within sexes but not between.
Territorial interactions between males are common throughout the year and involve males fighting one another in feet-first attacks directed the head and neck (Jenkins 1983). Birds often become entangled during these fights and tumble down through the vegetation before separating and alighting on exposed perches where they exhibit prancing displays, slowly flapping their wings and exposing the pure white of their neck and breast in one another’s direction (Jenkins 1983). Females have been observed perching quietly in the area during these interactions (Jenkins 1983).
Breeding: Ground doves likely breed year round, peaking between April and August (Craig 1996, Stinson 1993, Villagomez 1987). Drahos (1977) reported a peak season between January and June for Guam. Vocalizations tend to increase from April-July (Craig 1996) and Stinson (1993) reported that 14 nests were found on Saipan between April and September. Warner(1952) reports finding nests on Guam only in the first half of the year and Marshall (1949) hypothesized on the basis of physiological data that the ground doves breed year round. Jenkins (1983) on Guam reports observing: “ (1) an adult carrying nesting material in late May, (2) courtship and mating in September and mid-November, (3) recently fledged males in immature plumage in September and November, (4) territorial interactions between adult males year round, and (5) paired birds in all months of the year.” A Guam Division of Aquatic and Wildlife Resources biologist also reported an active nest in August 1964 (Jenkins 1983).
Mating usually takes place on a bare horizontal limb in a tall tree. The female alights on the limb and begins to walk along it toward concealment into the leafy part of the tree. The male then flies to the same branch and utters, as he alights, a long snarl which can be represented as “crrrreeeeeek”. She will often remain stationary and allow the male to preen her head and neck.
The male mounts three to four times, each event lasting 20-30 seconds. As copulation occurs the male will grab nearby small twigs and branches in a ritualized fashion. When the male mounts the female she often utters a short, raspy soft call, quite unlike the usual moaning call of the species. After this point the pair will separate and begin the whole sequence over again, the whole procedure lasting 4-5 minutes, after which the birds perch quietly in different parts of the same tree (Marshall 1949; Jenkins 1983).
Nesting: White-throated Ground Doves build a bulky nest in the canopy of littoral scrub or forest. Nests have been found in Cynometra spp., Elaeocarpus spp., Guettarda spp., Erythrina spp., Ficus prolixa, Artocarpus spp., Pandanus dubius, Bambusa spp., Leucaena leucocephala, and Hibiscus tiliaceus (Stinson 1993; Warner 1952; Drahos 1977; Jenkins 1983). Nest sites have been recorded in limestone forest, near roadside in limestone forest, and agro-forest (Stinson 1993). Stinson (1993) reported a mean nest height of 6.6m (range = 5-8 m; n = 5), mean estimated canopy cover of 37% (range = 10-60%; n = 5), and an estimated forest canopy height of 8.8 m (range = 5.8-12 m; n = 5).
Eggs, incubation, hatching, growth and development: Ground dove clutch size varies from 1- 2 eggs (Stinson 1993 and Jenkins 1983). Warner (1952) reported that both male and females participate in nest construction and incubation and D. Aldan reported a nesting ground dove that exhibited a broken wing display on Pagan (Stinson 1993).
Reference
Craig, R. J. (1996). Seasonal population surveys and natural history of a Micronesian bird community. The Wilson Bulletin, 246-267.
Drahos, N. (1977). Additions to the avifauna of Guam. Micronesica, 13(1), 45-48.
Jenkins, J. M. (1983). The native forest birds of Guam (No. 598.2 AME). Washington, D. C: American Ornithologists' Union.
Kibler, L. F. (1950). Notes on the birds of Guam. The Auk, 400-403.
Marshall, J. T. (1949). The endemic avifauna of Saipan, Tinian, Guam and Palau. The Condor, 51(5), 200-221.
Stinson, D. W. (1994). Birds and mammals recorded from the Mariana Islands. Natural History Research Special Issue, 1, 333-344.
Stophlet, J. J. (1946). Birds of Guam. The Auk, 63(4), 534-540.
Villagomez, E. C. 1987. Game bird (dove) survey and research. Pp. 37-46 in Commonwealth No. Mariana Is., Div. Fish Wildl. Prog. Ann. Report.
Warner, D. W. (1952). The avifauna of Micronesia, its origin, evolution, and distribution.
Wiles, G. J., Bart, J., Beck Jr, R. E., & Aguon, C. F. (2003). Impacts of the brown tree snake: patterns of decline and species persistence in Guam's avifauna. Conservation Biology, 17(5), 1350-1360.
Order: Columbiformes
Family: Columbidae
Chamorro Name: Paluman apaka
SPECIES OVERVIEW
Description: A sexually dimorphic, robust, short-tailed forest dove.
Adult Male: The forehead, face, chin, throat, and upper breast white, lightly washed with a pale buff. The crown, occiput, sides of head, and nape are rusty to dark brown, the remainder of the upper parts are dark bronze-olive. The feathers of mantle and upper wing coverts are broadly edged with metallic purple-violet, the primaries, under wing coverts and axillaries are brown. The tail, lower breast, under parts, bill and feet are dark brown.
Adult Female: Resembles adult male but smaller and with underparts between “ochraceous- tawny” and “cinnamon brown” in color. Head and neck are darker with more rufous than underparts while the remainder of upper surface resembles underparts but with striking olive green sheen, especially on upper wing-coverts. Primaries are brown but outer webs lighter and the tail is rufous brown with a broad black sub-terminal band. The iris of the female is grey or brown with a grey orbital skin. Although less common, an alternate female plumage resembling the adult male plumage has been documented and is described as follows: breast is light drab tinged with light brown and darkening anteriorly; the crown resembles that of normal female although darker and becoming lighter and grayer on neck and nape; the shoulder and wing- coverts compare favorably with that of adult male although lighter and with yellowish tinge; the back is bronzed olive-green as in normal female but the mantle exhibits a few purplish feathers characteristic of the male; abdomen area is “olive brown” with buffy brown edges to the feathers.
Juvenile/Immature: The immature male resembles the adult male but the head and nape are darker brown; the throat and upper breast may be browner and less white. Young males have more noticeable rufous tips on the feathers than females. The immature female resembles the adult female, but with more rufous coloring; the olive-green sheen on feathers is reduced or absent.
Distribution and Status: The White-throated Ground Dove is known to occur on the islands of Asuncion, Agrihan, Pagan, Alamagan, Guguan, Sarigan, Anatahan, Saipan, Tinian, Agiguan, and Rota in the Mariana archipelago. A population was found on Guam but was extirpated in the 1980's by the brown tree snake (Boiga irregularis; Wiles et al. 2003). The species also occurs on the Micronesian Island of Yap.
Subsequent analysis of data from all island-wide surveys (1982 – current), Rota Bridled white-eye VCP surveys (2002-2005), and BBS surveys (2000-2005) indicate a stable to decreasing trend of the species’ populations on Rota. Analysis of Saipan BBS data indicates a significant increase in ground-dove populations between 1991 and 2010.
Habitat: Ground doves occurs in native, secondary, agricultural, and tangan tangan (Leucaena leucocephala) forests, and in habitat mosaics that include open fields. Craig (1996) reported ground doves more frequently in native forests than disturbed habitats, and Jenkins (1983) found the species absent from savanna, wetland, and coastal strand habitats. Ground doves use a range of forest strata, with most of their time spent in either the canopy (45%) or on the ground (30%; Craig 1996).
Food and Feeding Habits: The species is primarily frugivorous but will consume seeds and some leaves and flowers of a wide variety of plant species. Craig (1996) observed ground doves foraging for seeds and probing leaf litter on the ground and feeding on the fruits of native trees, including papaya (Carica papaya). Although other species of ground doves from the same genus are forest under-story herbivores, the White-throated Ground Dove appears to be a microhabitat generalist (Craig 1996). Stophlet (1946) observed a female ground-dove picking at the underside of a leaf and assumed it was gleaning insects. There are no other references or documentation of ground-doves foraging for or consuming insects. Bender ([in review]) found ground doves to be seed predators after feeding trials of both native and non-native plants were executed on a captive setting on Saipan.
Behavior: The ground dove is secretive, solitary, and seldom found in pairs outside of the breeding season (Drahos 1977). The species is often observed flying high over forest canopy, leading Kibler (1950) to suggest that these long flights may indicate widely separated feeding grounds. Data collected by the CNMI DFW suggest that the species is territorial, often foraging singly on the forest floor and stopping to chase away conspecifics (Villagomez 1987). However, ground doves have been observed in groups of 8-15 on three different islands (Saipan, Aguiguan, and Rota; Villagomez 1987), and they appear to tolerate conspecifics that are greater than 10m away; males that approach other males within that distance are generally chased off (Villagomez 1987). Agonistic behavior was observed within sexes but not between.
Territorial interactions between males are common throughout the year and involve males fighting one another in feet-first attacks directed the head and neck (Jenkins 1983). Birds often become entangled during these fights and tumble down through the vegetation before separating and alighting on exposed perches where they exhibit prancing displays, slowly flapping their wings and exposing the pure white of their neck and breast in one another’s direction (Jenkins 1983). Females have been observed perching quietly in the area during these interactions (Jenkins 1983).
Breeding: Ground doves likely breed year round, peaking between April and August (Craig 1996, Stinson 1993, Villagomez 1987). Drahos (1977) reported a peak season between January and June for Guam. Vocalizations tend to increase from April-July (Craig 1996) and Stinson (1993) reported that 14 nests were found on Saipan between April and September. Warner(1952) reports finding nests on Guam only in the first half of the year and Marshall (1949) hypothesized on the basis of physiological data that the ground doves breed year round. Jenkins (1983) on Guam reports observing: “ (1) an adult carrying nesting material in late May, (2) courtship and mating in September and mid-November, (3) recently fledged males in immature plumage in September and November, (4) territorial interactions between adult males year round, and (5) paired birds in all months of the year.” A Guam Division of Aquatic and Wildlife Resources biologist also reported an active nest in August 1964 (Jenkins 1983).
Mating usually takes place on a bare horizontal limb in a tall tree. The female alights on the limb and begins to walk along it toward concealment into the leafy part of the tree. The male then flies to the same branch and utters, as he alights, a long snarl which can be represented as “crrrreeeeeek”. She will often remain stationary and allow the male to preen her head and neck.
The male mounts three to four times, each event lasting 20-30 seconds. As copulation occurs the male will grab nearby small twigs and branches in a ritualized fashion. When the male mounts the female she often utters a short, raspy soft call, quite unlike the usual moaning call of the species. After this point the pair will separate and begin the whole sequence over again, the whole procedure lasting 4-5 minutes, after which the birds perch quietly in different parts of the same tree (Marshall 1949; Jenkins 1983).
Nesting: White-throated Ground Doves build a bulky nest in the canopy of littoral scrub or forest. Nests have been found in Cynometra spp., Elaeocarpus spp., Guettarda spp., Erythrina spp., Ficus prolixa, Artocarpus spp., Pandanus dubius, Bambusa spp., Leucaena leucocephala, and Hibiscus tiliaceus (Stinson 1993; Warner 1952; Drahos 1977; Jenkins 1983). Nest sites have been recorded in limestone forest, near roadside in limestone forest, and agro-forest (Stinson 1993). Stinson (1993) reported a mean nest height of 6.6m (range = 5-8 m; n = 5), mean estimated canopy cover of 37% (range = 10-60%; n = 5), and an estimated forest canopy height of 8.8 m (range = 5.8-12 m; n = 5).
Eggs, incubation, hatching, growth and development: Ground dove clutch size varies from 1- 2 eggs (Stinson 1993 and Jenkins 1983). Warner (1952) reported that both male and females participate in nest construction and incubation and D. Aldan reported a nesting ground dove that exhibited a broken wing display on Pagan (Stinson 1993).
Reference
Craig, R. J. (1996). Seasonal population surveys and natural history of a Micronesian bird community. The Wilson Bulletin, 246-267.
Drahos, N. (1977). Additions to the avifauna of Guam. Micronesica, 13(1), 45-48.
Jenkins, J. M. (1983). The native forest birds of Guam (No. 598.2 AME). Washington, D. C: American Ornithologists' Union.
Kibler, L. F. (1950). Notes on the birds of Guam. The Auk, 400-403.
Marshall, J. T. (1949). The endemic avifauna of Saipan, Tinian, Guam and Palau. The Condor, 51(5), 200-221.
Stinson, D. W. (1994). Birds and mammals recorded from the Mariana Islands. Natural History Research Special Issue, 1, 333-344.
Stophlet, J. J. (1946). Birds of Guam. The Auk, 63(4), 534-540.
Villagomez, E. C. 1987. Game bird (dove) survey and research. Pp. 37-46 in Commonwealth No. Mariana Is., Div. Fish Wildl. Prog. Ann. Report.
Warner, D. W. (1952). The avifauna of Micronesia, its origin, evolution, and distribution.
Wiles, G. J., Bart, J., Beck Jr, R. E., & Aguon, C. F. (2003). Impacts of the brown tree snake: patterns of decline and species persistence in Guam's avifauna. Conservation Biology, 17(5), 1350-1360.
White-throated Ground Dove - Kasey Clarke