Grackles & Bluebirds

In addition to Messages that have appeared in the Bluebird Mailing Lists on this topic, the following are on the Audubon Society of Omaha website:  Predators and Problems On The Bluebird Trail

Will grackles bother bluebirds? Last year about mid summer there were flocks of grackles that would land in our yard and neighboring yards. I could tell Mom bluebird did not care for them because she would do her warning chirp. Also if she had food for the nestlings,she would not go to the nest box. I would chase the grackles away so she could continue feeding the nestlings. Mom bluebird had to do this chore by herself.

REL Hayden, Idaho

Rob Yaksich
ABQ, NM

Grackles will indeed bother bluebirds. In fact, Grackles will bother just about anything they can overpower. I saw a Great-tailed Grackle drive a Killdeer into deep water and bludgeon it to death with its long, sharp bill. Then it flew to an adjacent island adn did the same thing to another Killdeer, which barely managed to survive after I caught it and brought it in. I don't know what provoked the Grackle attack, but they seem to be pretty rapacious birds. I know they will eat the nestlings of open-nesting birds, including our resident population of Ring-necked Pheasants, Gambel's Quail and Mourning Doves. Now that White-winged Doves are rapidly expanding into the Middle RIo Grande, I imagine the Grackles will nibble on their babies too. Grackle numbers have absolutely gone through the ceiling here in recent years - especially Great-tails, which are bigger and stronger than Commons. What this means for cavity-nesters remains to be seen. The grackles have shown curiosity for the Wood Duck boxes, but haven't gone in one yet.

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Hello list: Had a visit yesterday from Tom Barber of Cambridge Ohio. He ask if I knew why he found a dead male eastern bluebird near it's nest box with it's head off? This same subject was discussed on this list earlier this spring with no positive answer to the question. Maybe its more common than we thought. Have others had this happen this year? Nest had week old eggs in box when the male is found near the box with head off. Both parts found with no signs of what happened. I told Tom that I'd ask the list about this to see if anyone knew what happened. The female stopped incubating shortly after the male was found dead. Thanks for any help on this. Joe Huber

Charter member NABS, Charter member OBS, Life member OBS Joe Huber
hubertrap"at"webtv.net

http://community.webtv.net/hubertrap/HOUSESPARROWCONTROL

http://community.webtv.net/hubertrap/RoostingBluebirds

Date: Fri, 11 Aug 2000 11:05:52 -0500
From: "dmccue" dmccue"at"usit.net
To: hubertrap"at"webtv.net, BLUEBIRD-L"at"cornell.edu
Subject: Re: Dead Male EABL

Greetings Joe - Glad you are enjoying the Ohio weather again.

I had this happen twice this season. Both however, were in the nest box and I considered it a rogue male sparrow. The head was not severed just mutalated. Dan McCue Camden, TN in west TN on the Tennessee River.

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Date: Fri, 11 Aug 2000 13:59:24 -0400
From: "Randy Jones" randyj"at"enter.net
To: hubertrap"at"webtv.net
Cc: "Bluebird Listserve" bluebird-L"at"cornell.edu
Subject: Re: Dead Male EABL

I found a female with her head off (head missing) about 75 yards from the nestbox in early April after laying two eggs. Never figured out what did it.

Randy Jones
Allentown PA
randyj"at"enter.net

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Date: Fri, 11 Aug 2000 17:46:43 EDT
From: Phl806"at"cs.com
To: randyj"at"enter.net, BLUEBIRD-L"at"cornell.edu
Subject: Re: Dead Male EABL

Missing heads typically point to Grackles. That is the MO they use to do away with their neighbors. 

Phil Berry
NW FLorida

Date: Fri, 11 Aug 2000 17:14:20 -0500
From: "Keith & Sandy Kridler" kridler"at"1starnet.com
To: "BLUEBIRD-L" BLUEBIRD-L"at"cornell.edu
Subject: RE: Dead bluebird :-(

Keith Kridler Mt. Pleasant, Texas

As Dan McCue noted, the House Sparrow while killing the other birds normally works on the hapless birds head. They do not eat the head so most of it will still be attached to the body. I have watched hawks kill and eat birds and also Loggerhead shrikes. They tend to strip the feathers off and eat the breast meat first. (The few I have been able to see close up in the wild!) Raccoons and 'possum's do not kill for fun and they normally eat all but the wings. If given a large number of birds they tend to leave the head, wings and tail section. The only animal I have observed just eating the head of a bird and leaving the rest of the body is the domestic cat. They are often well fed and some of our cat owning friends complain about their cats bringing "headless" birds home from time to time. I would tend to blame a cat if you found most of the bird because even a frightened 'coon will carry off a full ear of corn if you chase them out of the garden. Weasels and mink go into a killing frenzy in a large flock of birds and a male mink can kill
300 chickens in a night or a littler of puppies or kittens. They are fairly rare and cannot climb most bluebird nestbox mounting posts so this only leaves members of the squirrel or rat family if the bird is headless in a nestbox.

The following is a link to a web page telling about "chiggers". I learned a few new things about them. They are very numerous this year and now Fread
has me glad I never bought the insect repellant containing cypermethrin!

Thanks Fread for another excellent post! KK
http://www.ianr.unl.edu/ianr/lanco/enviro/pest/factsheets/008-96.htm

Date: Fri, 11 Aug 2000 21:22:29 EDT
From: N1hamilton"at"cs.com
To: BLUEBIRD-L"at"cornell.edu
Subject: Re: Dead Male EABL

Would cats be a possibility? I have indoor cats and when they caught mice in the basement they often would just eat(?) the head off and I'd find the poor mouse decapitated (not a pretty sight) but the rest of the mouse was intact
Nicole

Date: Sun, 20 Aug 2000 09:40:24 EDT
From: Sss2gemini"at"aol.com
To: BLUEBIRD-L"at"cornell.edu
Subject: Re: [BIRDCHAT] Headless dead small birds in garden

Sherry Hunter,
Byron Center, MI

Thought everyone would find this of interest, as this has been a recent topic here on the Bluebird list. This was posted on the BIRDCHAT list.

Greetings!

An interesting 'Dead Nestling' query appeared in the Question Box section of the Sept/Oct 2000 issue of BirdWatcher's Digest. In addition to some dead baby birds in the yard, a reader found a found a few small birds with their heads missing. The answer is quoted below:

"The decapitations are a predictable behavior of common grackles during their nesting season and a year-round habit of several small owls. Among grackles, the behavior is not well studied, but probably serves to reduce competition for resources within territories, and ecologically it could be a
pre-predatory stage of ongoing development within the species. Given enough time, grackles could become birds of prey in the same manner that shrikes are."

"Owls typically decapitate their prey to disable it and the headless body is eventually eaten, although it might be cached for a while. If you find decapitated birds during the summer, the culprit could be jay, magpie, crow, grackle or owl. After Labor Day the probability shifts to owls."

Patricia Rossi
Levittown, PA Lower Bucks County
circuscyan"at"aol.com

Date: Sun, 20 Aug 2000 10:16:26 -0700
From: Linda Violett
To: "bluebird-l"at"cornell.edu"
Subject: Re: Headless dead small birds in garden

Linda Violett - Yorba Linda, Calif.

Hawks also decapitate (young) birds.

As this List knows, I like to make closed-box visits to keep an eye on things at difficult sites. At a site where there was a hawk family in the area and I regularly find bluebird feathers after the fledge and see hawks chomping on mourning doves.

It was just after a bluebird fledge and I didn't want to bring undo attention to the nestbox or distract the bluebird family so I left my pole and lifter in the truck and slowly strolled the area and spotted some newly-fledged bluebirds in a nearby tree. The ever-present hawks were also in the area . . . three. Sorry, I don't know the type of hawk but they were mottled so I think they were young. Their call has is a quick four or five-note sequence that reminds me of a monkey.

Anyway, the bluebird family seemed to be content in their tree and I was walking back to my truck when I noticed one of the hawks land in a patch of thick grass along a slope. It was stalking and stretching to its full height and pounced on something. I thought it was a bluebird fledgling and I started walking back to investigate. The hawk flew to a tree and started picking away at its prey but I couldn't tell what it was.

Eventually, I heard a thud on the ground under the hawk and found the body of a decapitated large young bird. Sorry I don't know what kind of bird for sure, if I had to take a guess, I would guess it was a baby kestrel. In hindsight, I should have taken it home to the freezer for identification.

But I wanted to share that hawks also decapitate (young) birds.

...

Date: Sun, 20 Aug 2000 10:25:23 -0700
From: Linda Violett
To: "bluebird-l"at"cornell.edu"
Subject: PS: Headless

PS: The decapitated large young bird was only a nestling. Its feathers were growing out but not anywhere close to being flight-ready.

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