Blue Jay Croaks as Alarm Sounds

639 - BLUE JAY (2-8-2016) tradwinds park, broward co, fl -01

(Above is a beautiful public domain photo of a Blue Jay vocalizing that I found on Flickr. Click on it to go to the photographer's photo stream.)

I've been interested in a body of knowledge call "Bird Language" ever since Jon Young wrote the book "What the Robin Knows" in 2013. It describes and organizes patterns of bird behavior and sounds around perceived danger that he calls "alarms." If you can recognize when birds are exhibiting alarm behavior, you can sometimes determine what the source of that alarm is. I've found snakes in trees by first recognizing songbirds alarming around a particular area in the canopy. And I've gotten to see a few more Cooper's Hawks and Sharp-shinned Hawks over the years by recognizing other birds' alarms that the hawks trigger.

Blue Jays have always been difficult to interpret in this context. Sometimes you see them mobbing a hawk while making their "jeer" calls. But it seems like just as often, maybe even more often, they get together and jeer and jeer and jeer for no apparent reason.

But recently I made a discovery about Blue Jay alarms. Back in November one morning on Lake Creek Trail, I heard a nearby Blue Jay making jeer calls. And then I heard a low croak from the same direction. I found the Blue Jay and saw it make a few more croaks as it concentrated on a small area of low dense brush. Looking into this brush I was excited to see a roosting Eastern Screech-Owl!

Since then, I've been listening for these croaks from Blue Jays. And when I hear them, I can usually find both the Blue Jay and a hawk that it's harassing. The croaks seem to be a pretty reliable indicator that a Blue Jay is actively confronting some kind of predator. Much more reliable then the jeers.

A couple days ago I was able to record one of these croaks. A Broad-winged Hawk was perched in my neighbor's backyard and a Blue Jay flew in to harass it. I started recording audio on my phone hoping to record a croak, and I did! See the attached audio observation of Blue Jay. The audio clip starts out with some jeer calls, and then at about 10 seconds there is one croak. The Blue Jay made this croak as it dove at the hawk. It's the last Blue Jay sound on the clip.

I also attached the Eastern Screech-Owl observation from November when I first noticed this croak and wondered what it was.

Posted by mikaelb mikaelb, June 20, 2020 19:04

Observations

Photos / Sounds

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What

Eastern Screech-Owl Megascops asio

Observer

mikaelb

Date

November 17, 2019 08:34 AM CST

Description

Taken on Lake Creek Trail in Williamson County.

Found down a dirt side trail near the Braes Valley parking lot. I heard a Blue Jay making low croaking sounds I've never heard before, and found it hopping around a certain area in a dense bush. Something made me look at the Blue Jay through my binocs and then I found this little Eastern Screech-Owl roosting! The Blue Jay was agitated and sort of mobbing it. A couple Northern Cardinals came by and made lower chip notes as they noticed the owl and hopped around it a bit. The owl never moved.

Photos / Sounds

What

Blue Jay Cyanocitta cristata

Observer

mikaelb

Date

June 16, 2020 11:09 AM CDT

Description

This recording is of a Blue Jay harassing a Broad-winged Hawk. It's mostly the common jeer calls of the Blue Jay, but the last sound it makes (at about the 10 second mark) is a low croak. In my experience, this croak seems to be a good indicator that a Blue Jay is actually harassing a predator. The jeer call is so common and often has no obvious cause or reason.

Comments

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Interesting! I've found many ratsnakes, owls, and hawks by checking out blue jays, but I didn't know about the croak call.

Posted by cliftonladd 5 months ago (Flag)
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Thanks Clif! Have you figured out any other way to tell when the Blue Jays are actually harassing a predator, and when they're just making a bunch of noise for no apparent reason?

Posted by mikaelb 5 months ago (Flag)
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No, but usually if there are 3 or 4 blue jays making a fuss, there's something there. If I can't find it, then I usually assume it's there, but I just can't find it.

Posted by cliftonladd 5 months ago (Flag)

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