Seasonality in tropical birds and their survival

Many species are migratory, traversing considerable distances annually

by Lorenzo Ciotti
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Seasonality in tropical birds and their survival

Birds have more or less developed wings; the only ones without wings are the moa and elephant birds, both extinct between the 11th and 18th centuries. The wings consist of specialized arms, and most species are able to fly.

Flightless birds include ratites, penguins, and various island species. Some birds, such as penguins and anseriformes, are specialized swimmers. Others, such as corvids and parrots, are among the more intelligent animals, capable of using tools and bequeathing non-congenital behaviors, in effect forming a kind of culture.

Many species are migratory, traversing considerable distances annually. Birds are social: they communicate by visual cues, calls, songs, and participate in other social behaviors, including cooperative breeding, hunting, flocking, and cooperative preying on predators.

Most birds are temporarily monogamous, while others demonstrate polygynous and polyandrous behaviors. The eggs are usually brooded and incubated in the nests. Seasonality in tropical birds study, published in the Journal of experimental zoology.

Part A, Ecological and integrative physiology, explained: "The survival of offspring depends on environmental conditions. Many organisms have evolved with seasonality, characterized as initiation-termination-reinitiation of several physiological processes (i.e., body fattening, molt, plumage coloration, reproduction , etc).

It is an adaptation for the survival of many species.Predominantly seasonal breeders use photoperiod as the most reliable environmental cue to adapt to seasonal changes but supplementary factors like temperature and food are synergistically involved in seasonal processes.

Studies from diverse vertebrate systems have contributed to understanding the mechanism involved in seasonal reproduction at the molecular and endocrine levels.Long-day induced thyrotropin (thyroid-stimulating hormone) released from the pars tuberalis of the pituitary gland triggers local thyroid hormone activation within the mediobasal hypothalamus.

This locally produced thyroid hormone, T3, regulates seasonal gonadotropin-releasing hormone secretion. Most of the bird species studied are seasonal in reproduction and linked behavior and, therefore, need to adjust reproductive decisions to environmental fluctuations.

Reproductive strategies of the temperate zone breeders are well-documented, but less is known about tropical birds' reproduction and factors stimulating the annual breeding strategies. Here, we address seasonality in tropical birds with reference to seasonal reproduction and the various environmental factors influencing seasonal breeding."