Y

Ornithology of Tobago - Bird Lists in alphabetical order started with "Y":

yellow-bellied seedeater Sporophila nigricollis SPARROW

Order: Passeriformes Family: Emberizidae
Identification Tips: Length 11.5cm (4.5in)
Was a common resident of Tobago but have unfortunately been excessively trapped for use as cage-birds and their numbers have declined. They are found in cultivated areas, forest margins and the move up the mountains during the wet season.
Adult male: Black head, neck and upper breast. Matt olive green upperparts. Pale yellow for the rest of underparts. Pale blue-grey that appears whitish.
Adult female and Immature: Olive brown upperparts. Yellowish-buff underparts with paler abdomen. Grey.

A boring series of musical notes delivered from an exposed perch. Also utters a cheep when excited.
Breeds: June - September. Nest Location: In small tree or bush and takes 5-12 days to build. Nest Type: A cup shaped nest flimsily made with roots and grass. Clutch size: 2-3, eggs pale turquoise or buff, size 17x12mm. Length of Incubation: 12 days by the female for 80% of the time. Days to Fledge: 10, and fed by both parents with regurgitated seeds and insects. Number of Broods: 4.
Diet: Primarily seeds with lesser quantities of insects and spiders.

yellow-billed cuckoo Coccyzus americanus CUCKOO

Order: Cuculiformes Family: Cuculidae
Identification Tips:
A small to medium sized bird with uniform brown plumage covering the wings and body. The loose webbed plumage actually accounts for half the cuckoos body weight. Under its long tail are two columns of four to six large white circles. The lower portion is a yellow colour that gives this bird its common name - the bill is short to medium in length and somewhat curved.
They have zygodactylous feet, meaning that of the four toes, the middle two point forwards and the outer two point backwards.
Sexual differentiation does not exist, except in size. The differences were recently discovered with the separation of C. americanus into two subspecies, C. americanus americanus (the eastern version) and its western counterpart, C. americanus occidentalis. Mean tail lengths differed by 6.95mm (0.275in), with western tail lengths greater than those of the eastern species. Bill length and maxilla depth were also significantly greater in the western species. Behavioural and ecological variations have been correlated to differences in morphology. C. americanus is statistically larger in tail, wing, and bill length, and maxilla depth in the western regions of North America than those found in the eastern regions. These variations in bill and wing length and maxilla depth were also consistent with the tail findings comparing males with females.
Habitat: throughout the New World, with the exception of some oceanic islands and extreme high latitudes. Lives in a multitude of habitats, ranging from forests to open woodland. Winter months spent in the tropics like Tobago.
Diet: mainly insectivorous, the cuckoo predominantly preys on hairy caterpillars and cicadas. Their diet also includes bird eggs, snails, small vertebrates such as frogs and lizards, berries and some fruit. The young mainly eat regurgitated insects from parents.
Breeding: these cuckoos are monogamous in their breeding patterns. Pair bond behaviour includes the offering of sticks and other nest materials by the male to the female. This is followed by a 'flick' of the female's tail 180 degrees up in the air. Courtship feeding is also common. The calling male will mount the perched female's shoulder and place food in her mouth. The male then copulates with the female.
The nest is made of twigs, lined with roots and dried leaves, and rimmed with pine needles. It is incomplete at the onset of laying. Clutch size: 4, but can range between 1-8, depending on certain biotic and abiotic factors, such as food availability and temperature - eggs are a light blue fading to a greenish-yellow and are about 31mm (1.2in) long. Biparental care is illustrated by shared male and female incubation periods. The eggs have a very short gestation period and young hatch asynchronously. The newly hatched offspring are altricial, meaning that they are helpless, blind and naked. Ordinarily, from the point of fledging, the young will climb branches in 7 days, and fly within 21 days. Soon thereafter they leave the nest. The male will usually take care of the first fledgling, and the female will care for the rest.
Breeding normally coincides with that of the cicada and/or caterpillar. Studies have shown that in times of prey abundance, production of eggs will increase, which leads to an increase in brood parasitism by C. americanus. Brood parasites are defined as species that do not build their own nests or raise their own offspring. By increasing the clutch size and synchronising hatching with periodical cicada eruption further increases the occurrence of brood parasitism. This positive reproductive response to the increased abundance of prey indicates exceptional adaptive value. This plasticity is a regular aspect of C. americanus breeding biology.
Habitat: can be found in forest to open woodlands, those areas with dense undergrowth such as parks, riparian woodlands and thickets are considered their favoured habitats.

yellow-breasted flycatcher Tolmomyias flaviventris

TYRANT FLYCATCHER
Order: Passeriformes Family: Tyrannidae
Identification Tips: Length; 12.7cm (5in)
Rare and Breeds in Tobago.

Slate grey head. Whitish lores. Greyish green upperparts. Brown edged wings with yellowish green. Brown tail. White throat and yellowbreastboth streaked with black. Yellow mid-abdomen. Orange-yellow iris. Black above and paler below, long and flat. A surprising loud chee or tee-dee.

Breeds: June - September. Nest Location: In mangroves slung from thin branch 2.4m (8ft) above ground. Nest Type: An elliptical pouch made of dry grass. Clutch size: ? Length of Incubation: ? by both parents. Days to Fledge: ? Number of Broods: ?
Diet: Primarily insects.

yellow-crowned night-heron Nyctanassa violacea HERON

Order: Ciconiiformes Family: Ardeidae
Identification Tips: Length: 54cm (21in) Wingspan: 112cm (44in)
Sexes similar Fairly small, long-legged, short-necked heron. Tucks neck in close to body in flight and often at rest, rarely extending it. Black bill. Leg colour varies with age, as with black crowns. Long legs, with feet and part of legs extending beyond tail in flight.
Adult: Red eyes blue-grey neck, chest,backand belly. Dark centres tobackfeathers. Pale yellowish forehead and buffy-white crown. Black face andchin with broad white auricular stripe.

Juvenile: Eyes yellowish to amber. Head, neck, chest and belly dark grey-brown streaked finely with buff and white. Darker cap. Wings andbackdarker brown with small white spots at the tips of the feathers. Greater secondary coverts with crisp white edgings and small spots at tips.
Immature: Gradually acquires adult plumage over 2 years, losing spotting and streaking and gradually acquiring face and body plumage of adult.
A high-pitched hoarse quaak.
Similar species: Adult unmistakable. Immatures separated from american bittern by pale spotting on the upperwing, reddish eye, lack of black neck spot, different shape, stouter bills and more even upperwing colouration in flight. Juvenile separated from juvenile black-crowned night-heron by pale edgings on greater secondary coverts, smaller spots about head and neck, larger bill and longer legs. Immatures can show a variety of plumage characters so are best separated from immature black-crowns by their larger, thicker bill and longer legs, although if remnants of juvenile plumage or the first hints of adult plumage can be seen, the identification should be simplified.

Breeds: March - August. Nest Location: In forest margins next to fresh water. Nest Type: Nests are very difficult to find. Clutch size: 2-4. Length of Incubation: 21-25 days. Days to Fledge: 25. Number of Broods: 1? Diet: Almost exclusively aquatic invertebrates with lesser quantities of fish.

yellow-headed caracara Milvago chimachima FALCON

Order: Falconiformes Family: Falconidae
Identification Tips: Length:
A bird of the savannah, forest margins and swamps, this is a rare visitor.
The yellow-headed caracara is a rarely seen raptor in Tobago but very common Panama to northern Argentina. It has a habit of patrolling roads looking for carrion. It is fairly small with a characteristic pale head with dark stripe behind the eye. In flight it shows a conspicuous white patch on its long wings. Apart from road kills it eats insects including caterpillars, frogs, fish and natural carrion.
It sits on thebackof cattle where it normally picks off ticks but is also known to eat the flesh from open wounds. A high-pitched scream, shriii-oo.

An adult was seen at Bon Accord, 18 011997 to 11 05 1998. In both 1997 and 1998 it was observed carrying nesting material, but a potential mate and the nest eluded detection; this is the first nesting attempt for Tobago since it first appeared in 1987, they are breeding now and have been seen since at Kariwak Village.
Diet: Being omnivorous, it eats anything like carrion - dead animals, fish, birds' eggs and chicks, seeds, snakes, lizards and insects.

yellow-legged thrush Platycichla flavipes THRUSH

Order: Passeriformes Family: Turdidae
Identification Tips: Length: 22cm (8.5in)
A common resident and Breeds in Tobago.
Adult male: Black overall . Some have black and dark grey back, flanks and lowerparts. Narrow eye-ring. Yellow legs. Yellow.
Adult female: Olive brown upperparts. Ochre brown underparts. Yellow-brown legs. Yellow or blackish.
Immature: As adult Buff tipped crown feathers and upperparts. Black and yellow barred and mottled throat and breast.
A spectacular thrush song with imitation manakin and spinetail song thrown in.
Breeds: January - August. Nest Location: In a niche in a bank or a rock in a ravine. Nest Type: Large cup shaped nest is built of plant stems and moss, lined with fine roots. Clutch size: 2 eggs light turquoise or light blue with reddish brown markings. Length of Incubation: ? days. Days to Fledge: ?. Number of Broods: ?
Diet: Almost exclusively fruits with lesser quantities of insects.

yellow oriole Icterus nigrogularis ORIOLE

Order: Passeriformes Family: Icteridae Common name: golden oriole, small cornbird
Identification Tips: Length: 20cm (8in)
Usually bright golden-yellow - the colour of the inside of a mango, hence it is also called the golden oriole. Black lores, tail and throat. Wings are black with white edges. Varies from a musical flute-like phrase of three to five notes to a harsh and oft' repeated cack.
Immature: Duller yellow without most of the black features.

Seen widespread in suburban areas, open woodlands and along the edges of forests and mangrove swamps.
Breeds: January - August. Nest Location: They make these nests hung from branches. They make numerous nests which is fortunate as the piratic flycatcher are known to force them off their nests to live 'rent free'. Nest Type: Nests are made from grass and palm tree fibres into long pendulous tube about 45cm (18in) long with the entrance near the top. Clutch size: 2-4 eggs whitish with dark brown markings. Length of Incubation: ? days, both parents feed the young. Days to Fledge: ?. Number of Broods: ?
Diet: Feeds on insects and other invertebrates found among the foliage. Likes small fruits and nectar.