Friday, February 16, 2018

All About Townsend's Warblers

Here is a recent post from the Union Bay Watch Blog published by Larry Hubbell, long-time local photographer and birder. 

Here also is an in-depth article about Larry and his work.

Living Sunshine

A Townsend's Warbler is one of my favorite birds. I love the alternating patches of brilliant yellow. Catching just a glimpse of one makes me smile. I can almost feel the warmth of summer sunshine on my face. When most Townsend's Warblers are soaking up Vitamin D in Mexico or California a hardy few choose to stay here during the gray of winter. 

Normally, they prefer to feed in the upper foliage of coniferous trees, but apparently in winter they are sometimes forced to look for food wherever they can find it. In winter I often see them searching among the blossoms of the flowering Mahonia in the Arboretum. 
This particular plant variety, 'Arthur Menzies', creates a bit of a conundrum for folks, like myself, who believe native plants are better for our local environment. This plant supplies winter food for the native Townsend's Warblers and also for Anna's Hummingbirds. Even though this variety of plant was discovered in the Arboretum, I do not think we can honestly call it a native. It is a hybrid of two Chinese species. You can read the interesting back story by Niall Dunne, Communications Manager, Arboretum Foundation, by Clicking Here.
One of the most odd features of Townsend's Warblers is how their color schemes vary depending on your perspective. When viewed from behind, they appear mostly black and white. If I only saw one departing, without a glimpse of yellow, I might not even realize the bird was a warbler.
When they spread their tails, you can see that the black and white color scheme extends to end of their rectrices or tail feathers.
When observed face-to-face a male bird appears mostly black and yellow. As they flicker through the foliage it is easy to overlooking their two white wing bars.

At first glance, a mature female looks pretty much the same as a male. You might even assume that the difference is due to the lack of sunlight in this photo. That is not the case. Females are a dark, olive green in color on their crowns and auriculars, e.g. sides of the head, while mature males have black in these locations.

Another critical difference can be seen in the primarily yellow throats of the females... compared to the black throats of the males.

Curiously, the male throats do not all have the same amount of black.

This male shows a lot less black, but perhaps, growing a black throat is a process. Occasionally, mature females can also have a bit of black on their throats, however, their cheeks and crowns will still be olive-green.

Among both the males and females, their backs are olive green with small dark spots. Given their propensity to feed high in the trees it is easy to miss their green and black backs.
As you can see from the last few photos, these birds are often found gleaning food from the branches of conifers in the winter. Last month I found them mostly in the Pinetum, while this month, I am seeing them more in the Winter Garden among the Mahonia blossoms.

Juvenile Townsend Warblers lack the black feathers and have a paler shade of green than the mature females.
In addition, they have less markings on their sides, just below their wings. Since the younger birds, both male and female, look virtually the same we are unable to determine their gender.
The black on this bird's head helps us to conclude it is male.

However, when the bird looks down, we can see olive green with black spots on its crown.

This is the same bird, which we saw earlier, with a minimal amount of black on its throat. I am assuming that these characteristics indicate we are looking at a youthful male who is in the process of molting and growing in its mature black coloring.
While it is fun to try and deduce the gender and age of these little birds, truthfully, I am always just pleased to spot such a brilliant little warbler. Especially one who foregoes the sunshine of Central America to share the winter with us.
Most life on earth depends on sunshine for survival, but warblers are one of the few who give proper due to their life source. To me their brilliant coloring looks like sunshine come to life.

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