Hello! Most of my posts take place around San Diego County, (Mostly Lake Murray) unless otherwise noted.
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Monday, June 14, 2010

Grackles and Killdeer Chicks

Great tailed grackle in tree

Lake Murray has a large population of great-tailed grackles. They have pretty much taken over the lake and are heavily concentrated in M2's territory. That could be why M2 and his gal have been fighting with Little Male over the south side of the territory--to find a safe place for their chicks. But, Little Male won't give up his feeding grounds that easily. Also, it's not all that safe, grackles sometimes go there along with a few crows and small raptors.

So far, I haven't seen any really bad behavior on behalf of the grackles except for one time when they tried to steal food out of M2's mouth. I think he gave the grackle a sharp peck with his beak, but otherwise seemed unworried about the big black bird, who backed off. It's possible that the grackle didn't get more aggressive because I was there, or it felt like it wasn't worth it. But, M2 seemed pretty much unconcerned about the bird. I have heard about grackles killing an adult killdeer, but I haven't seen any real aggression between the two species yet. (I did see a grackle aggressively harass and peck heavily a large white-winged dove at a Borrego Springs bird feeder recently for no apparent reason).

However, I am almost 100% positive that the grackles will eat any of the killdeer chicks that might be running around that area. While I do think the killdeer could defend itself pretty good if it was alert and ready for a grackle attack, I fear that the grackle will actually kill a parent to get to a chick.

So far, I haven't seen any harm come to ducklings as they are mostly ignored by the grackles. I don't think the mother ducks like them and that could be why they moved them out of that area quickly. The family of five used to hang out near the grackle nesting area when the ducklings were very young until the grackle chicks started to fledge.

M2 avoids being near the grackle nesting area, now very busy with fledging chicks. He used to go over to that area a lot, but has since stayed away as about a dozen of them are nesting in the trees there. Hopefully, the grackles won't be territorial when it comes to their fledgelings and my fears of one of them killing M2 or his mate may come true.

I am sure that F3, M2's mate, has already laid her eggs (they mated a week ago), but perhaps in another male's territory. M2 was calling her last time I saw him, but there was no sign of her. M1 has a "safer" area to nest in but people walk around that area and sometimes a hawk comes by. M4 has ravens firmly established in part of his territory. I haven't seen M8 in a while. M6 and M7 may have safe nesting spots, but I have seen no breeding activity in those areas except for the fights over a female.

It would seem that only M3 and M5 (the ones living in a fenced off area near the treatment plant) have the safest nesting area with few grackles, hawks, crows or ravens. But, I can't see them, so it looks like I won't be able to see or photograph any killdeer chicks at the lake this year or even the next few years if the grackle population stays high.

Strangely, there have been few true large blackbirds at Lake Murray recently. They used to be extremely common there until recently.

So, will the rise of the grackles mean the demise of the killdeer or other birds in the area?

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