Blue jays

[Jace Wesley Brasher]

Hello, this morning I experienced a male blue jay protecting a tree from other males. After he had won the battle he went to the feeder got some peanuts and went back to his tree. As he sat at the very top of the tree he started to bounce up and down and make a rattling sound. I have never seen anything like this before, even after 14 years of watching them. Does anyone know why he was doing this? Why is it not on ebird or Audubon?

[Nathan Pieplow]

Jace,

The rattle calls of jays have been shown to be given by females, usually dominant females. If they are ever given by males, it's apparently very rare. So this sounds to me like a case of a dominant female asserting her dominance at your feeder.

eBird and Audubon don't have this kind of detailed information on bird behavior. The place to get that is the Birds of North America online, which is a subscription service. 

Another good resource is petersonbirdsounds.com, the website that accompanies my Peterson Field Guide to Bird Sounds. There you can listen to examples of the Blue Jay rattle calls, among many other sounds the species makes. (There is even an example of a Blue Jay imitation of a Cooper's Hawk, to tie in an earlier COBirds thread.)

On Mon, Jul 8, 2019, 9:28 AM Joe Roller <jrol...@gmail.com> wrote:

Jace,

Layman's answer = educated guess.

Many species have a pecking order, with more dominant and more submissive members, as you know. 

Most birds, especially males, defend breeding territories, again, common knowledge.

Some have more loosely defined winter feeding territories, which they may defend, usually not

as vigorously.

That Blue Jay behavior seems to be a dominant male (OR FEMALE) defending a food supply.

The rattling sound and bouncing  movements I assume are "threat displays" like human males "putting up their fists"or shouting or standing taller.

Nathan Pieplow describes a Blue Jay rattle "all year" by females" on p 307, "Peterson field guide to bird sounds of western North America" but males vocalizations are highly variable, so not sure of gender of your jay.

Joe Roller, Denver

Cool observation. Try to record it next time.

And give details of behavior in a comment section or your eBird report for that day.

 

On Mon, Jul 8, 2019 at 8:14 AM Jace Wesley Brasher <vwj...@gmail.com> wrote:

Hello, this morning I experienced a male blue jay protecting a tree from other males. After he had won the battle he went to the feeder got some peanuts and went back to his tree. As he sat at the very top of the tree he started to bounce up and down and make a rattling sound. I have never seen anything like this before, even after 14 years of watching them. Does anyone know why he was doing this? Why is it not on ebird or Audubon?

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[Joe Roller]

Thanks for taking your time to provide this valuable and intriguing answer,

Nathan.

Joe

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