Blue Jay Problem

[clever...@gmail.com]

We have a blue jay problem, and I’m not talking about the one where they consume all the peanuts within minutes after putting them out – although we do have that problem, too. For the last few weeks they’ve been pecking the paint off the trim boards along the bottom of a short section of wall. When I shoveled snow high enough to cove the affected area, they moved down the trim board and continued mining paint. At least two of the ten or so blue jays frequenting our feeders have engaged in this destructive and unwelcome behavior.

 

Little did I know that this is a “thing” with blue jays. It’s been widely reported, especially in the NE US where acid rain depletes the soil of naturally occurring calcium. The behavior is most often seen in winter, and scientists theorize that blue jays are caching paint chips for the calcium, something they need for egg laying in the spring. They don’t believe that the jays are eating the paint chips but rather are gathering them into their crops, flying off, and then stashing them for later. Corroborating evidence comes from bird feeders with this problem who have been able to deter the jays from doing this by putting out eggshells for the jays to carry off. There’s even a name for consuming non-food items for mineral supplementation: geophagy.

 

Fortunately our paint dates from the post-lead era, but there could be other additives generally not considered health food for jays. After I covered the affected length of wall they seemed to stop, but if not we have eggshells at the ready.

 

Steve Wilson

Isabella             

[clever...@gmail.com]

One cautionary note I didn’t include is that raw eggshells can carry salmonella which can be very dangerous for the birds. Just to be safe, the Cornell website recommends sterilizing them by boiling or heating in a 250 oven for 20 minutes. I probably should have included that in my email.

 

From: Anne Uehling <astew...@gmail.com>
Sent: Thursday, January 22, 2026 8:32 AM
To: clever...@gmail.com
Subject: Re: {Ely Field Naturalists} Blue Jay Problem

 

I will start putting egg shells in my feeder.

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[Mary M White / Charles R Neil]

Just looked it up... freezing does not kill salmonella, so boiling would be the best solution. Thanks, Steve

C Neil, Embarrass

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[chip hanson]

Baking works well also

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[Carl Karasti]

Boiling eggs, or egg shells, will leach a small portion of calcium (and other minerals) out of the egg shells. It's a pretty small amount, but some people traditionally use the water from boiling their eggs as a soil amendment which adds calcium and other minerals from the shells to improve the soil.

Chip's suggestion of baking the shells before offering them to the birds would not remove any calcium or other minerals, meaning baked shells would provide a bit more mineral value for the birds than would boiled shells.

Carl Karasti

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[clever...@gmail.com]

Numerous studies have found that boiling has a negligible effect on the calcium carbonate in eggshells, and they are still considered a rich source of calcium, which is why Cornell Lab of Ornithology included it as an option, along with heating eggshells in a 250 oven for 20 minutes. So if boiling is the easiest method for someone, the blue jays are not likely to notice the difference.

 

Steve Wilson

Isabella