Canario
Golden White-eye (Cleptornis marchei)
Order: Passeriformes
Family: Zosteropidae
CHamoru Name: Canario
SPECIES OVERVIEW
Description: A sexually monomorphic forest bird with head, rump, and underparts light cadmium and back orange-citrine in color (Baker 1951). Wings and tail are brownish with orange-citrine outer edges and whitish inner edges; breast, belly, side, and tail coverts raw-sienna in color (Baker 1951). Orbital ring, under wing-coverts, and axillaries are yellow, and bill and feet yellow-brown (Baker 1951).
Distribution: The Canario occurs only on Saipan and Aguiguan. Engbring et al. (1986) estimated the populations for the species in 1982 as 55,500 and 2,300 individuals on Saipan and Aguiguan, respectively. Later DFW and USFWS bird surveys of these islands yielded mean abundance estimates for the species of 71,997 on Saipan in 2007 (95% CI 47,586 – 106,535; Camp et al. 2009) and 15,499 on Aguiguan in 2008 (95% CI 10,383 – 22,277; Amidon et al. in review). On Aguiguan, surveys have been conducted in 1992, 2000, and 2002 (Craig et al. 1992; DFW 2000, 2002). In addition to these historical records, recent investigations on Tinian and Rota have revealed prehistoric evidence of the species on both islands (Steadman 1999).
Habitat: Canario occur in all wooded habitats on Saipan, including native limestone forest, introduced Leucaena leucocephala thickets, strand forest, and suburban areas; however, they are generally absent from swordgrass savannah (Stinson and Stinson 1994, Craig 1996). Research on nesting densities in native limestone forest and L. leucocephala thickets suggests that the species nests predominately in the native forest (Sachtleben 2005). Engbring et al. (1986) suggested that Canario does well in virtually all woody vegetation types, especially brushy areas that are abundant in plants with small leaves or leaflets.
Food and Feed Habits: Canario feed primarily on foliage invertebrates, flying insects, nectar, fruits, and to a lesser extent on flowers, of at least 18 species of plant (Table 2; Craig 1990 and 1996). The species forages by probing and gleaning, predominantly in the top outer portion of trees in both native limestone and tangantangan forests (Craig 1990). They tend to forage on fruits and dead leaves more than live leaves and flowers, and spends more time on all available substrates other than live leaves, especially branches (Craig 1990). Overall, the Canario is a more generalized forager than the Nosa (Zosterops conspicillatus), and is less specialized in the use of tree zones, foraging surfaces, and foraging methods than the latter (Craig 1990).
Behavior: Flocks of Canario exhibit a harsh, raspy tchup or schick calls and a quick, loud whistle (Pratt et al. 1987). The song of the species is an extended rambling warble (Pratt et al. 1987), which is often sung in the off-key and, albeit more drawn out, is reminiscent of that of the Warbling Vireo (Vireo gilvus) of North and Central America (P. Radley, personal obs.).
The Canario is a territorial species that tends to forage in family groups; adjacent or overlapping groups will show intolerance and aggression towards one another (Craig 1990). Craig (1996) observed banded males defend territory boundaries against adjacent males and respond, although not vigorously, to playback of recorded Canario song. Of the four species of small forest passerine on Saipan this species only shows regular interspecific aggression towards Nosa (Craig 1990). Craig (1990, 1996) documented only a few instance of Canario chasing Naabak (Rhipidura rufifrons), a species that often seeks out the former for assistance during foraging.
Breeding: The Canario likely breeds year-round with distinct peaks in breeding during different times of year. Sachtleben (2005) recorded nesting from February to June and Craig (1996) recorded breeding activity from January to August and in October. Pyle et al. (2012) reported birds on Saipan in breeding condition every month of the year, with a small gap in time from mid-August to early September when no birds were observed exhibiting brood patch or cloacal protuberance.
Nesting: Nests are cup shaped, unlined, and composed of Casuarina equisetifolia needles, grasses, vine tendrils, and hairs (Stinson and Stinson 1994). Thalia Sachtleben (pers. comm., 2005) recorded the dimensions of 44 Canario nests, reporting a mean nest height of 69 mm (range = 47-98 mm), a mean nest cup depth of 42 millimeters (range = 32-53 mm), a mean
Canario have been reported building nests on 11 tree and two vine species (Table 2). Thalia Sachtleben (pers. comm., 2005) recorded the nest site characteristics of 74 golden white-eye nests in 2004. The mean distance of these nests from the ground was 3.0 m (range = 1.2 – 5.0 m). The mean height of the nest trees were 5.3 m (range = 0.8 ‒ 11.2 m) and the mean distance of the nests from the boles of the nest tree were 66 cm (range = 0 ‒ 295 cm). The average number of support branches supporting each nest was three (range = 2 ‒ 6) and the average diameter of these support branches was 3 mm (range = 1 ‒ 8 mm).
Eggs, Incubation, Hatching, Growth, and Development: Typical clutch size of the Canario is two (n = 11; Baker 1951, Stinson and Stinson 1994) and eggs are pale blue, without gloss, and spotted with rufous but more densely at the wider end (Baker 1951). Eggs tend to be 20 mm in length and 15 mm at their widest point (Baker 1951). Stinson and Stinson (1994) found that incubation, which is undertaken by both sexes, typically lasts 14 days and that young fledge from 10 to 14 days after hatching.
Nests were observed every three days (occasionally four) and nestlings could only be aged with certainty if they were found on Day 0 (hatch day) or Day 1. Chick development appeared to be quite variable, and was presumably dependent on the number of young per nest, experience of the parents, and availability of food.
Day 0: Chicks approximately 2 – 2.5 cm in length, naked, with dark-medium pink skin and no down.
Day 1: 2 – 2.5 cm in length, naked, with medium pink skin.
Day 3: Overall length from 3 – 4.5 cm, wing pin length from 2 – 5 mm, with back and head pins
either barely erupting or at 1 – 2 mm in length, skin medium-dark pink in color, with eyes
closed and no down.
Day 4: Approximately 3.5 – 4.5 cm in length, with wing pins at 6 – 7 mm and back pins at 2 – 3mm (or back and wing pins visible but ≥1 mm), skin medium – light pink in color. Day 6: Approximately 4.5 – 5.0 cm in length, with wing pins at 7 – 10 mm and olive feathers
erupted from back and wing, head pins at 2 – 4 mm and back pins at 4 – 6 mm, with any exposed skin light-medium in color, and eyes still closed(?).
Day 7: Approximately 4.5 – 5.0 cm in length with exposed skin pale pink in color, wing pins at 6 – 7 mm and back and head pins at 2 – 3 mm.
Day 9: Approximately 5 – 6 cm in length, fully feathered, downy, and often perched on the rim of the nest cup. Feathers turning golden in color, head tracts visible, eyes open, no tail or wing pins <10 mm, with feathers erupted ~10 mm from back pins, but head feathers barely erupted.
Day 10:Approximately 5 – 6 cm in length, some pin tracts still exposed or fully feathered, olive back feathers or feathers golden, feathers erupted from wings 8 – 10 mm in length, and the tail ~ 10 mm long.
Day 12:Approximately 6 – 6.5 cm in length, fully feathered, golden, eyes open, tail ~ 10 mm, and bare throat. Any young force-fledged at this age flew well.
Threats: The Canario is currently abundant and widespread on Saipan, less so on Aguiguan, and is not currently considered threatened or endangered by the Federal or Commonwealth governments. Because of its limited distribution, however, the species is considered a Bird of Conservation Concern by CNMI DFW. The IUCN (2012) lists the species as Critically Endangered because Saipan my harbor an incipient population of the brown tree- snake (Boiga irregularis; Colvin et. al. 2005), which is exacerbated by the white-eyes limited distribution, and Saipan’s proximity to Guam, the known stronghold of the invasive tree-snake. The primary threats to the species are newly introduced predators, such as the brown tree-snake, or avian diseases (e.g., West Nile virus, avian pox, etc.).
Golden White-eye (Cleptornis marchei)
Order: Passeriformes
Family: Zosteropidae
CHamoru Name: Canario
SPECIES OVERVIEW
Description: A sexually monomorphic forest bird with head, rump, and underparts light cadmium and back orange-citrine in color (Baker 1951). Wings and tail are brownish with orange-citrine outer edges and whitish inner edges; breast, belly, side, and tail coverts raw-sienna in color (Baker 1951). Orbital ring, under wing-coverts, and axillaries are yellow, and bill and feet yellow-brown (Baker 1951).
Distribution: The Canario occurs only on Saipan and Aguiguan. Engbring et al. (1986) estimated the populations for the species in 1982 as 55,500 and 2,300 individuals on Saipan and Aguiguan, respectively. Later DFW and USFWS bird surveys of these islands yielded mean abundance estimates for the species of 71,997 on Saipan in 2007 (95% CI 47,586 – 106,535; Camp et al. 2009) and 15,499 on Aguiguan in 2008 (95% CI 10,383 – 22,277; Amidon et al. in review). On Aguiguan, surveys have been conducted in 1992, 2000, and 2002 (Craig et al. 1992; DFW 2000, 2002). In addition to these historical records, recent investigations on Tinian and Rota have revealed prehistoric evidence of the species on both islands (Steadman 1999).
Habitat: Canario occur in all wooded habitats on Saipan, including native limestone forest, introduced Leucaena leucocephala thickets, strand forest, and suburban areas; however, they are generally absent from swordgrass savannah (Stinson and Stinson 1994, Craig 1996). Research on nesting densities in native limestone forest and L. leucocephala thickets suggests that the species nests predominately in the native forest (Sachtleben 2005). Engbring et al. (1986) suggested that Canario does well in virtually all woody vegetation types, especially brushy areas that are abundant in plants with small leaves or leaflets.
Food and Feed Habits: Canario feed primarily on foliage invertebrates, flying insects, nectar, fruits, and to a lesser extent on flowers, of at least 18 species of plant (Table 2; Craig 1990 and 1996). The species forages by probing and gleaning, predominantly in the top outer portion of trees in both native limestone and tangantangan forests (Craig 1990). They tend to forage on fruits and dead leaves more than live leaves and flowers, and spends more time on all available substrates other than live leaves, especially branches (Craig 1990). Overall, the Canario is a more generalized forager than the Nosa (Zosterops conspicillatus), and is less specialized in the use of tree zones, foraging surfaces, and foraging methods than the latter (Craig 1990).
Behavior: Flocks of Canario exhibit a harsh, raspy tchup or schick calls and a quick, loud whistle (Pratt et al. 1987). The song of the species is an extended rambling warble (Pratt et al. 1987), which is often sung in the off-key and, albeit more drawn out, is reminiscent of that of the Warbling Vireo (Vireo gilvus) of North and Central America (P. Radley, personal obs.).
The Canario is a territorial species that tends to forage in family groups; adjacent or overlapping groups will show intolerance and aggression towards one another (Craig 1990). Craig (1996) observed banded males defend territory boundaries against adjacent males and respond, although not vigorously, to playback of recorded Canario song. Of the four species of small forest passerine on Saipan this species only shows regular interspecific aggression towards Nosa (Craig 1990). Craig (1990, 1996) documented only a few instance of Canario chasing Naabak (Rhipidura rufifrons), a species that often seeks out the former for assistance during foraging.
Breeding: The Canario likely breeds year-round with distinct peaks in breeding during different times of year. Sachtleben (2005) recorded nesting from February to June and Craig (1996) recorded breeding activity from January to August and in October. Pyle et al. (2012) reported birds on Saipan in breeding condition every month of the year, with a small gap in time from mid-August to early September when no birds were observed exhibiting brood patch or cloacal protuberance.
Nesting: Nests are cup shaped, unlined, and composed of Casuarina equisetifolia needles, grasses, vine tendrils, and hairs (Stinson and Stinson 1994). Thalia Sachtleben (pers. comm., 2005) recorded the dimensions of 44 Canario nests, reporting a mean nest height of 69 mm (range = 47-98 mm), a mean nest cup depth of 42 millimeters (range = 32-53 mm), a mean
Canario have been reported building nests on 11 tree and two vine species (Table 2). Thalia Sachtleben (pers. comm., 2005) recorded the nest site characteristics of 74 golden white-eye nests in 2004. The mean distance of these nests from the ground was 3.0 m (range = 1.2 – 5.0 m). The mean height of the nest trees were 5.3 m (range = 0.8 ‒ 11.2 m) and the mean distance of the nests from the boles of the nest tree were 66 cm (range = 0 ‒ 295 cm). The average number of support branches supporting each nest was three (range = 2 ‒ 6) and the average diameter of these support branches was 3 mm (range = 1 ‒ 8 mm).
Eggs, Incubation, Hatching, Growth, and Development: Typical clutch size of the Canario is two (n = 11; Baker 1951, Stinson and Stinson 1994) and eggs are pale blue, without gloss, and spotted with rufous but more densely at the wider end (Baker 1951). Eggs tend to be 20 mm in length and 15 mm at their widest point (Baker 1951). Stinson and Stinson (1994) found that incubation, which is undertaken by both sexes, typically lasts 14 days and that young fledge from 10 to 14 days after hatching.
Nests were observed every three days (occasionally four) and nestlings could only be aged with certainty if they were found on Day 0 (hatch day) or Day 1. Chick development appeared to be quite variable, and was presumably dependent on the number of young per nest, experience of the parents, and availability of food.
Day 0: Chicks approximately 2 – 2.5 cm in length, naked, with dark-medium pink skin and no down.
Day 1: 2 – 2.5 cm in length, naked, with medium pink skin.
Day 3: Overall length from 3 – 4.5 cm, wing pin length from 2 – 5 mm, with back and head pins
either barely erupting or at 1 – 2 mm in length, skin medium-dark pink in color, with eyes
closed and no down.
Day 4: Approximately 3.5 – 4.5 cm in length, with wing pins at 6 – 7 mm and back pins at 2 – 3mm (or back and wing pins visible but ≥1 mm), skin medium – light pink in color. Day 6: Approximately 4.5 – 5.0 cm in length, with wing pins at 7 – 10 mm and olive feathers
erupted from back and wing, head pins at 2 – 4 mm and back pins at 4 – 6 mm, with any exposed skin light-medium in color, and eyes still closed(?).
Day 7: Approximately 4.5 – 5.0 cm in length with exposed skin pale pink in color, wing pins at 6 – 7 mm and back and head pins at 2 – 3 mm.
Day 9: Approximately 5 – 6 cm in length, fully feathered, downy, and often perched on the rim of the nest cup. Feathers turning golden in color, head tracts visible, eyes open, no tail or wing pins <10 mm, with feathers erupted ~10 mm from back pins, but head feathers barely erupted.
Day 10:Approximately 5 – 6 cm in length, some pin tracts still exposed or fully feathered, olive back feathers or feathers golden, feathers erupted from wings 8 – 10 mm in length, and the tail ~ 10 mm long.
Day 12:Approximately 6 – 6.5 cm in length, fully feathered, golden, eyes open, tail ~ 10 mm, and bare throat. Any young force-fledged at this age flew well.
Threats: The Canario is currently abundant and widespread on Saipan, less so on Aguiguan, and is not currently considered threatened or endangered by the Federal or Commonwealth governments. Because of its limited distribution, however, the species is considered a Bird of Conservation Concern by CNMI DFW. The IUCN (2012) lists the species as Critically Endangered because Saipan my harbor an incipient population of the brown tree- snake (Boiga irregularis; Colvin et. al. 2005), which is exacerbated by the white-eyes limited distribution, and Saipan’s proximity to Guam, the known stronghold of the invasive tree-snake. The primary threats to the species are newly introduced predators, such as the brown tree-snake, or avian diseases (e.g., West Nile virus, avian pox, etc.).
Canario - John Bender