Friday, October 30, 2020

All About Winter Birds At Union Bay

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


The Dark Side

A Varied Thrush feeding on Sorbus in the Arboretum.

This time of year it feels like we are on the dark side of the Sun. In reality, the actual distance is fairly consistent year-round. However, the slope of the Earth's polar axis is angling our hemisphere away from the Sun. The increasing shade will peak on December 21st. During the Winter Solstice, we will experience almost twice as much darkness as light. 

Many of the bird species, that breed around Union Bay, have already headed south. They are chasing the warmth, light, and available food. For those of us left behind, life outdoors is decidedly quieter. There are fewer lifeforms to hear and see. Our skies are grayer, the days are dimmer and the rainfall is more persistent. With the pandemic, plus, the economic and social strife, this may be the most challenging winter of our lives.

Finding a single Varied Thrush feels like a breath of fresh inspiration. Like a sign that life will persist. If we watch closely we will also notice - the hearty, resident, year-round birds who simply shake off the rain, find food and endure. 

Additional inspiration is on its way, there is a steady stream of winter birds who are heading south. They are coming to take advantage of our winter rain. Our rain brings warmth which helps to keep their food free from snow and ice, while our latitude provides just enough daylight to allow them to find the needed nutrition. 

Varied Thrush are shy birds that like to breed in old-growth forests throughout Alaska and Western Canada. In the Fall, some of them return to the Arboretum. Attracted, at least in part, by fruit-bearing trees. They are not alone.

The fruit also attracts American Robins...

...and Cedar Waxwings. The bird on the right is an adult. Its chest is clean and clear without vertical striping. 

In the Fall, chest stripes indicate a waxwing who hatched-out earlier in the current year.

Surprisingly, even fruit specialists, like waxwings, are not one hundred percent frugivorous. Particularly, in Spring they eat insects and no doubt feed them to their young. 

Nonetheless, this time of year waxwings are far more likely to be seen eating fruit. 

The biggest surprise for me this time of year is how many other species of birds can be found in and around the same fruit trees.

While watching the activity in a Sorbus tree a Downy Woodpecker flew in and landed overhead in a neighboring Western Red Cedar. The cedar provided both of us with shelter from the rain. If a Waxwing eats roughly eighty percent vegetation and twenty percent animal matter the Downy is just the opposite. It was apparently mining the moss for virtually invisible insects.

Near the malus, where I spotted the American Robins, there were a surprising number of other visitors. 

A Dark-eyed Junco searched the ground for food.

A Song Sparrow landed on an inner branch, apparently more interested in what it might find in the lichen and moss.

Steller's Jays consistently visited the area. As mentioned in the post, Steller's Delight, I have seen them collecting and eating acorns but I have yet to see one eating fruit. 

Curiously, I did watch one fly into the middle of a Malus tree. The tree was densely packed with fruit, robins, and waxwings. The jay descended in hops via the inner branches. Finally, it disappeared into the snowberries - surrounding the base of the tree. After a few minutes, it hopped back up and into view before taking to the air. 

If this had happened during Spring I might have suspected it was taking food to its young or raiding the nest of a vertically-challenged bird. It makes me wonder, What was it doing? Could it have been searching for fallen fruit on the ground?
 
American Crows often passed overhead, cawing loudly. However, so far, I have never seen them eating fruit. Given the wide variety of foods they consume, their avoidance of fruit seems very surprising.

I have seen Northern Flickers eating fruit, but maybe it is their last resort. This bird totally ignored the crabapples, apparently, there must still be some ants to be found. 

A Chickadee that visited the malus also appeared hesitant to settle for fruit.

A Red-breasted Nuthatch worked its way down one of the trunks.

With its head-down approach, it appeared to be totally focused, on finding a crevice to hide a fall seed for winter consumption.

Particularly refreshing was watching a Bushtit in the malus. I have never seen or even imagined a Bushtit eating fruit. They prefer small creatures. However, from what I have read, they do eat some vegetation.

In this case, the Bushtit was looking all around.

Logically, I would suspect it was scanning... 

...for small creatures to consume.

Although, for a moment it appeared to be considering the fruit.

The little bird sat for an uncommonly long time.

Maybe it was carefully considering what the waxwings and the robins were consuming.

It appeared to take a close look at the fruit before giving up and flying away.

The most consistent behavior I noticed in the last week is whenever the frugivores are harvesting fruit other species tend to gather around. I suspect they congregate because it is safer. The more eyes and ears that are watching and listening for danger the less likely it is that a predator can successfully sneak up on any individual. 

Plus, their diversity almost certainly helps. A Dark-eyed Junco has a better chance of seeing a predator approaching at ground level, the Cedar Waxwings and the American Robins are more likely to notice one flying overhead, and the Red-breasted Nuthatch is well placed to see one climbing up the trunk of a tree. A mixed flock, with its diversity of skills and abilities, seems clearly safer than one bird or even a single species by itself.


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