A perennial question we get at Maine Audubon is from folks who have woodpeckers “attacking” their homes. I’ve written about that issue here before; this usually stems from presumably young birds attempting to find food. Hopefully, for the homeowner’s sake, there isn’t any food (e.g., insects) living in their siding, and it also tends to be temporary. Another temporary home destroyer that Kay and Shep Shepardson wrote in about this week is the blue jay. While some of the solutions may sound similar, the reason for jays’ home attack is entirely different.

First off, it is surprisingly common to observe blue jays “attacking” a house, and in particular going after the paint. Project FeederWatch is a citizen science project by the Cornell Lab of Ornithology that asks anyone with a bird feeder to report what birds they see at their feeders through the winter and did a study on this devilish jay behavior in the late 1990s. The root of this behavior is that the jays are looking for sources of calcium to supplement their diet, and many paints get their pigments from sources like limestone or chalk (calcium carbonate). The FeederWatch study asked volunteers to see which birds would take extra sources of calcium and remarkably nearly 40% of observers documented this in blue jays.

So how to fix this? First, let’s call this the “If you can feed ’em, join ’em” solution: Since they are apparently looking for a calcium source, give them one! You can put out crushed eggshells as an alternative to your paint; just make sure that you sterilize them first by boiling or heating them in a 250ºF oven for 20 minutes.

The other solution, similar to dealing with destructive woodpeckers, is a deterrent. Try to put something between the jays and the place they’re stripping your paint. Since this behavior is generally short-lived, there is no need to use something permanent or “pretty.” I’ve had success hanging tin pie plates; they are fairly cheap, easy to punch a hole in and tie a string through, are light, blow in the wind, and reflective so they scatter light. Tin foil is another option, especially if the jay is using a larger area. You can hang sheets of tin foil with tacks, or even try wrapping it around the target areas. I will note that the Shepardson’s didn’t specify if their sidings were painted, just that they were wooden. I’ll encourage anyone with similar issues, be it from jays or woodpeckers, to make sure you fix any pest problems before any bird problems.

TELLING EAGLES APART

Did everyone hear about the Steller’s sea eagle that was in Boothbay in January? I’m sure you did, but among that Russian vagrant and the many bald eagles who call Maine’s coast home, there was also an immature golden eagle seen! Visiting birder Melissa Roach spotted the golden eagle soaring south of Factory Cove in Boothbay on Jan. 8, and I’m pretty sure that is the first time anyone has seen THREE species of eagles at the same place and time, anywhere in the country! While nothing will match the rarity of the Steller’s sea eagle, it is worth noting that golden eagles are also very rare in Maine and should always be very carefully identified. Given the amount of questions that came up after the golden eagle sighting, I wanted to provide a quick primer to eagle identification in Maine.

I want to start by acknowledging that golden eagles are probably one of the most commonly misidentified birds in Maine. It takes about five years for bald eagles to get their adult plumage, including that “bald” white head, and it is especially in their first year of life that they can be very dark overall (including the head). These all-brown eagles are often reported to us as goldens, probably with the same frequency that large coyotes get called wolves in Maine (which is a lot). A more diagnostic plumage characteristic is obvious when you see the birds in flight: look for where the bird shows white in the wing. On our immature bald eagles, they’ll show white on the inner part of the wings, the smaller “coverts” (what we could colloquially refer to as the bird’s “armpits”). The golden eagles that we get in Maine are almost all immature birds, which show white at the base of their flight feathers (the inner primaries and secondaries), and their coverts are all dark.

Size is definitely the hardest thing for observers to reliably distinguish, and it’s actually not a helpful field mark for telling bald from golden eagles. Reports of “goldens” usually say “it was HUGE! Much larger than a bald eagle” but golden eagles are only larger by mass, while bald eagles actually have a slightly longer wingspan. It was really interesting to receive reports from all over the state when people were looking for the Steller’s sea eagle, most people indicating that “it had to be the Steller’s because it was so big!”

There is an underappreciated bias in our perspective when identifying birds, especially when judging size, and it is best exemplified by the full moon, and what is known as the “moon illusion.” I won’t go into the full explanation here, but you’ve probably observed the “moon illusion.” You see a huge full moon rising above the horizon, but a couple of hours later it is back to looking like a normal-sized moon when it is higher in the sky. The moon obviously didn’t change size (or effectively get any farther away), but the way your mind perceives its size based on the objects around it is quite the optical illusion. This same effect makes us bad at judging the size of birds flying on the horizon as well.

All of the observer biases you’ve likely heard about with eyewitnesses, and why their recounting of events can be so flawed, is true with bird watchers as well. I’m sure we get things right most of the time (or is that just confirmation bias?) but it is good to be aware of how wrong we can be. When in doubt, take a picture! The resolution on most modern smartphones is remarkable, and even very low-quality photos can show important diagnostic field marks.

Do you have a nature question for Doug? Email questions to ask@maineaudubon.org and visit www.maineaudubon.org to learn more about backyard birding, native plants, and programs and events focusing on Maine wildlife and habitat. Doug leads free bird walks on Thursday mornings, 8 to 10 a.m., at the Gilsland Farm Audubon Sanctuary in Falmouth.

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