White Thoated Magpie Jay - Costa Rica's Vocal Tropical Birds

White Throated Magpie Jay

October 7th, 2013 by Anamaya Resort

Biology

White-throated magpie jay of Costa RicaOne of the New World jays, the white-throated magpie-jay is a big blue, black and white bird that features a sprightly black plume. It is primarily found in tropical dry forests, and goes along this habitat through its southern limit in Guanacaste, Costa Rica, turning it over to its close counterpart, the black-throated magpie-jay, around Jalisco, Mexico. In the the dry season, white-throated magpie-jays feed l on fruits, especially those of ant-acacias. After insect activity is stimulated by rains, they focus on insects, especially the larvae of large lepidoperans.

The White-throated Magpie-jay is between 43–56 cm (17–22 in) in length and weighs 205–213 g (7.2–7.5 oz). The species has a strangely long tail, and a slightly bent crest of feathers on the head. The crest is dark in the nominate race, but has blue or white margins on the other two subspecies of the magpie. The nominate race has a white face with a dark crown and margin to the face, forming a narrow strip around the throat, as well small spots below the eye. The dark color is less extensive in the other subspecies. The breast, belly and lowerside of the rump are white, and the wings, mantle and tail are blue. The legs and eye are black, and the bill is grey. The plumage of the females is much like the male only slightly duller above, with a tapering band running around the chest, and the tail is slightly smaller.

White-throated magpie-jays are large, vividly colored birds with long tails and crest feathers. Body weight typically ranges from 205 and 213 g and body length from 46 to 56 cm. Sexual dimorphism is evident in tail length, with females having much shorter tails (267 to 314 mm) than males (284 to 334 mm). Males and females are similar in measurement. Their wingspan typically ranges from 178 mm to 193 mm. Tarsus length ranges from 39 to 46 mm and bill length from 29 to 34 mm. Adult white-throated magpie-jays have mostly white face and ventral coloration with rich blue dorsal feathers. Both males and females have a black ring that runs across their breast, beginning behind the eye. Males and females can be distinguished by coloration, with a thinner and often incomplete black ring in males. Males also have partially white crests and little dark coloration above the eye. In contrast, females tend to have almost entirely dark crests, and much black or black-and-white mottled coloration above the eye. The auricular patch is black in both sexes, but much more pronounced in females, often blending into the breast ring.

White throated magpie jays generally breed from January to April. Females lay 2-6 eggs at a time. The females breeder is then responsible for hatching all of the eggs of a small group of birds and seldom moves away from its nesting habitat. According to their ingenious social structure, females from the group are in charge of bringing food to for the mother during the incubation process. White-throated magpie-jays male do not play any dominant role in caring for the brood. The hatching period lasts for about a month. They usually breed once in the early part of the year, however if the first nest collapses, the birds will continue to lay more eggs. The white throated magpie jays reach sexual maturity between 8 to 14 months.

The white-throated magpie-jay is a big blue, dark and white corvid. Its name is derived from the long blue, white-tipped tail, reminscent of that of a magpie. Its upper portion is blue and lower portion is white and the species has a black necklace, a distinct black pattern on the face, and a curling dark plume starting just above the neck. First, the middle retrices of the tail of the black-throated magpie-jay are very long and somewhat droopy at their tips, resulting in a streamer-tailed look when flying.

White-throated magpie-jays are one of the most noticeably vocal species where they are found, and their vocal talents are incredible. As such, a list of sounds specific to white-throated magpie-jaysare virtually impossible to reproduce. However, at least 14 functionally distinct classes of vocalizations have been described, and some of these are used much more frequently than others.

The White-throated magpie-jays are highly social and their breeding in usually cooperative. Though unusual among birds, the female offspring stay in the group and help their parents raise future broods, while male offspring is more detached and moves away from the group. Therefore, groups generally consist of a dominant female, her sole social mate, and a number of retained female offspring who feed the dominant female, nestlings, and fledglings. However, dispersing males have the permission to enter territories and accompany groups while foraging. Floaters may visit multiple groups in a day, and group males show slightly more aggression to them unless the dominant female is fertile.

White-throated Magpie-jays are omnivorous, feeding on a wide range of animals and vegetation. Their diet includes invertebrates such as insects and caterpillars, frogs, lizards, eggs and nestlings of other birds, seeds, fruits, grain, and nectar from blossoms. Younger birds take many years to develop the full range of foraging abilities of their parents.

Their social system is rather evolving and lays the foundation for a complicated mating system. Dominant females are generally faithful to their mates, but not entirely, with paternity going to both visiting magpies and to neighboring group males. Occasionally, a helper will start a nest of her own. Interestingly, the helper is not stopped from doing so, but the group will not help her unless the nest of the dominant female collapses. In addition, helpers may act as brood parasites on the nests of their own mothers, thus laying eggs for the group to raise. Both sexes, therefore, compete for mating opportunities. Thus the complex social structure includes intense competition – males for a chance to mate with the dominant female and females to achieve the dominant position within the group.

Reproductive twists within the magpie groups seem to have lead to the evolution of one of the more fascinating vocal systems in the magpie bird world. Male magpie-jays can individually produce upwards of 60 known vocalizations and probably more but they do so in an irregular situation than other creatures. When a magpie-jay of either sex encounters a low-threat predator or even an harmless species such as a dove, they may fly slowly and directly at the threat, screeching loudly. In this context males are capable of creating a wider range of chirps, and clinks. One possible explanation is that because male magpie-jays do not protect any possessions required by females, their best opportunity to be noticed by females is during predator confrontations, when groups must pay attention to specific warning sounds.

Another commonly heard vocalization is produced when a female and her mate are communicating for nesting attempts. These calls are given during pair formation. The two creatures (and sometimes other group members) move anxiously in close vicinity to each other, producing a medium range.

Where To Spot Them

In northwestern Costa Rica and southwestern Nicaragua, the magpie-jay prefers dense tropical forests. Primarily inhabiting forest peripheries, these creatures thrive in cattle ranches and at the edge of community settlements where solitary nesting trees can be found. However, their most prefered habitat seems to be a combination of open space for nesting and dry forests for feeding. Magpie-jays may be extremely dependent on ant-acacias for dry-season foraging and territories with acacia stands prove to be much more productive.

White-throated Magpie-jays was earlier spotted only as far south as the Nicoya Peninsula in Costa Rica, and remained in the lowlands on the Pacific Slope. Current deforestation has allowed the species to head southwards beyond Parque Nacional Carara, where it is now recorded regularly, and upwards of the Pacific Slope to Santa Elena, just below Monteverde Rainforest.

The White-throated Magpie-Jay range covers areas from from Mexico to Central America. These intriguing aerials can be found in Mexico and almost asll Central American countries like Costa Rica, Nicaragua, Honduras ,El Salvador and Guatemala. These creatures prefer a dry climate and hence thrive in dry forest lands. The Guanacaste Province of Costa Rica features a huge population of white-throated magpie-jays. They can also be spotted at National Parks across Costa Rica such as Carara National Park, Palo Verde National Park and Monteverde Cloud Forest Reserve.

More Info

White Throated Magpie Jay in Costa Rica – Lots of info from Costaricajourneys