Vermont woods are quieter now, with the departure of warblers and other migratory birds. We are left with our favorite winter friends: chickadees, nuthatches, kinglets, and blue jays (among others).

Close-up of a blue jay feather, by 2017 photo intern Rachael Drinker

Blue jays are considered nest robbers, predatory bullies eating the eggs and young of other birds. Even John James Audubon depicted a blue jay devouring eggs from a bird nest in one of his paintings.  However, blue jays are much more vegetarian than carnivore or omnivore. An 1897 study by F. E. L. Beal examined 297 stomachs of blue jays from 22 states and Canada. Only 5 of them contained egg shells and/or parts of birds. Blue jays mostly eat seeds, nuts, and some insects. Very occasionally they eat small vertebrates. 

In 2016, we had a very dry year in Vermont, and trees were stressed. This year most Vermont trees are reacting by producing a larger number of seeds than normal.  We call that a heavy mast year. Apple trees had more apples than ever, white pines are heavily laden with clumps of cones, oaks are drooping with many acorns, and beech trees developed many beech nuts. This provides great food for wildlife here in Vermont, including hungry blue jays.

The blue jay's top food choice is not eggs from other nests, but nutritious acorns. Jays hold acorns with their toes and peck away at them with their beaks to open them and eat them. Blue jays can fit up to four acorns in their crop (a pouch in their esophagus.) They store acorns in their crop, fly away and then cache them, or hide them in different locations to eat later. Like squirrels, blue jays do not remember all their acorn cache locations and so they are planting oak trees. Blue jays are responsible for increasing the expansion of oak trees after the last glaciation.

Have you ever found a blue jay feather on the ground? Bright blue stands out against dried leaves in the November woods. However, blue jays are not blue. The pigment, or coloration, in their feathers is brown, but microscopic structures in their feathers reflect light in just the right way that we see blue. This is like how we see cloudless skies as blue.  If you hold that feather you found up with the sun shining through behind it, you will see the true color- grayish brown. Then lower the feather in front of you and you will see it is blue again.

Bright blue jays bring color to the brown world of November, but not all blue jays stick around. A small percentage of Blue Jays migrate each year, forming huge flocks of 250 birds flying together down the Atlantic coast. No one knows why these jays choose to migrate-individual birds will migrate one year, and then stay put the next year. Birds that stay are often found in widely different areas. This behavior may be based on the availability of those favorite foods-acorns and beech nuts. Since we are having bumper crops of tree seeds this year, we expect to see plentiful bright blue jays in our woods and at our feeders this winter. Keep an eye out for these bright birds on your next outside adventure. 

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