Thursday, March 26, 2015

Hummingbird Babies

A female Rufous-tailed Hummingbird sits motionless on her eggs only inches above people passing underneath her.

The ecotourists on their way to dinner at La Salva Lodge, Costa Rica, don't notice her just off the canopied trail in the rain.

Broad leaves conceal and protect her as she patiently incubates her eggs. Keeping her eggs warm and dry during the frequent rains will require 15-17 days of attention.

To go unnoticed for that long she needs to be discretely feathered. Her rufous tail is her only showy feature. Yet still, most of her tail is hidden.  

A few miles away at the La Selve Biological Station, a Band-tailed Barbthroat Hummingbird rests on her nest. She too, wove it herself.

Shaped from twigs and other plant matter, woven with spider's silk, she hangs suspended over a pond. The leaf provides her with protection from the rain.

She looks wary, but if she felt threatened by our passing she would have flown off. She didn't.

It is safe to assume she is incubating eggs, too.

A new generation of Rufous-tailed Hummingbirds has hatched at Savegre Lodge in the Talamanca Cordillera mountains of Costa Rica.

Having hatched from an egg smaller than a green pea and now still only the size of a peanut shell, the pair rests defenselessly.

Remaining motionless, eyes closed, they wait for their mother's return.

Mother rufous-tailed drops to the edge of the nest and immediately freezes to avoid attracting attention.

But, the hungry babies can't wait and give away their location...three feet high in a four foot bush.

Consisting of mashed-up midges and gnats combined with nectar, these feedings will continue for weeks at the nest, still longer after they fledge.

The feedings take place deep down the throat.      
It seems unfair that the male hummingbirds get all the attention, while the female does most of the work of raising the next generation, but it works out that way. By necessity female birds are less colorful. How and why it evolved this way I can't explain, other than to say female birds choose the most colorful males more often. Color may be an indicator of health and strength in the female's mind.

A male Magnificent Hummingbird rests on an equally beautifully adorned branch. Always wary, but faster than his enemies, he glows in the late morning sun. Common to the mountainous reaches of Costa Rica, although reaching into Southeastern Arizona, too, the Magnificent Hummingbird is a rare find in the USA.


Credit: Cornell Lab of Ornithology, All About Birds
Credit: The Sibley Guide to Birds
Credit: The Birds of Costa Rica, Richard Garrigues & Robert Dean