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Nature’s Ways ... The blue jay — our largest, regular birdfeeder guest

by on February 20, 2020 1:51 PM

Each fall when the acorns matured, one bird species would flock to the row of pin oaks in front of the high school where I taught. Their noisy calls, large size and bold colors made them easy to identify. Blue jays - sometimes a dozen or more — would come in at one time to feast on the tiny acorns. When their crops are full, they carry one acorn away to hide in the nearby forest.

The largest bird to regularly visit Pennsylvania bird feeders is the colorful blue jay, Cyanocitta cristata. It measures about 10 inches long and sports a large crest on top of its head. It wears a distinctive blue, black and white coat of feathers. Both sexes have similar plumage.

Blue jays are boisterous at bird feeders, pushing out other species until they get their fill. They also announce their presence with a variety of loud and often unusual calls. They can mimic other birds’ calls, including those made by hawks. Some calls are so odd that a youngster hearing one for the first time remarked, “I thought that it was a UFO.”

This species was initially harmed by our invasion of its forest habitat. More recently, it has adapted to and even benefited from human presence. During the early 1900s, blue jays were considered deep woods birds, but by the end of the century, they inhabited cities and suburbs as well as forests. Some ornithologists credit the westward expansion of the jay’s range to their widespread use of bird feeders.

According to the Pennsylvania Game Commission, crows, ravens and blue jays are very susceptible to West Nile virus, so their population declined drastically in the late 19190s. However, the population rebounded by 2004 and evidence suggests that surviving birds have developed an immunity to the virus.

Blue jays are very common across their range. Ornithologists use three main tools to track their population. Volunteers helping with the second Pennsylvania Breeding Bird Atlas (2004-09) found blue jays in 98 percent of the total atlas blocks. This compares to the 95 percent found during the previous survey period of 1983-89.

Cornell Lab of Ornithology data is another method. In Pennsylvania, the 600-700 Cornell Project FeederWatch volunteers have observed blue jays at 88-92 percent of their feeding stations during the three most recent winters for which data is complete. For the winters of 2016-17, 2017-18 and 2018-19, blue jays ranked as the 6th to 9th most commonly-reported species. This is slightly lower than their 5th to 7th-place ranking for the three winters following the turn of this century.

Last, Breeding Bird Survey counts of blue jays in the Keystone State have been increasing through most of the past 30 years. The only exception was a several-year downturn in some local populations - likely because of West Nile virus. Although population size is difficult to assess, there are upwards of a half-million blue jays that call Pennsylvania home.

The diet of blue jays consists of beechnuts, acorns, insects, berries and seeds. Cornell Lab of Ornithology seed preference experiments show the same varied tastes: sunflower seeds, milo, whole corn and suet. They are the only feeder bird that swallows sunflower seeds whole. Other species, such as cardinals or chickadees, break open the seed and eat only the center heart.

Blue jays are also one of the few birds that caches acorns and other food for later use.

According to Doug Gross, ornithologist for the Pennsylvania Game Commission, the blue jay is a “keystone bird” of the eastern deciduous hardwood and mixed forests of much of North America. Because of its caching tree seeds, jays inadvertently plant deciduous trees - particularly oaks and beeches - in new places.

Blue jays are also known as “nest robbers,” killing and eating the young and eggs of other bird species. I have observed a pair of catbirds repeatedly chasing a blue jay near my home. It appeared that the catbirds were defending their nest.

I remember well a Pennsylvania Game News magazine cover that was painted by the late Ned Smith — a revered Pennsylvania wildlife artist. Smith’s painting showed a blue jay defending its nest from a raiding red squirrel. In other words, one well-known nest robber was trying to turn the table on another.

Here’s an odd report — A dozen years ago, blue jays were observed stripping and apparently eating the paint from houses. Biologists hypothesize that they might have been using the paint as a source of calcium. You can supply birds their needed calcium, and save your house, by offering broken pieces of egg shells. The shells should first be baked for 20 minutes at 250 degrees to kill any salmonella bacteria that might be present. Then crush the shells into tiny pieces. I am sure that egg shells are much better for birds than paint chips.

Blue jays will nest at a wide variety of locations and heights, but they seem to have a preference for conifers, such as hemlocks. I have only ever discovered one blue jay nest, about 15 feet up a hemlock tree.

Although they nest anytime from April through August, their average time for nesting is late May. Nestlings are nearly featherless when hatched. This, of course, is the origin for the saying, “naked as a jaybird.”

The crow family, to which the blue jay belongs, is known for birds that have great memories and above average problem-solving skills, and this species is no exception.

A quick survey of printed descriptions reveals blue jays to be described as bold, beautiful, flamboyant, brash, noisy, cunning, shy, pushy, mischievous, seed-hogging, and adaptable, among others. It is clear that humans are quite divided as to how to view this common year-round resident of the Keystone State.

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