Shelter Cove, California. 2009 Update

[stan kostka]

Hello All,

Just a short update here on the pilot nestbox program we have been running at Shelter Cove, on the northern California coast, as described in Updates 17(2) and 18(2).

We installed one small cluster of nestboxes in 2002, and they sat vacant until 2007, when one box was used by an ASY pair. Following up on this event, in 2008, we increased the number of nestboxes at the original site, and installed more boxes at several additional locations around Shelter Cove. In 2008 4 pairs used nestboxes: 3 pairs used boxes at the original site, and one box at one of the new sites was used in it's first year. This surprised us since it took so many years for the original boxes to be used.

Well, 2009 surprised us again. This year we found 10 pairs of martins using nestboxes at 4 locations around Shelter Cove ! Additionally, an eleventh pair used a Troyer horizontal gourd at a fifth site, the first time Purple Martins have nested in a gourd in California, to the best of our knowledge. The gourd site was initiated independently by a Shelter Cove resident, and was not officially part of our project, but a member of our team gave them the idea.

Martins continued to use holes in snags and wooden utility poles around Shelter Cove as well. And, we found three new locations where martins are nesting in various kinds of holes in the roofs and walls of peoples houses, some of these holes were apparently used by starlings earlier in the season.

All told, the known population of martins at Shelter Cove doubled this year. To the best of our knowledge this is the first and only sustained used of nestboxes by martins in California.

Looking forward to next year.

Stan, on behalf of the entire Shelter Cove team.

[LarryMelcher/KY]

Stan,
Thanks for the update, and thanks for all you and your crew is doing with Purple Martins in California.

You mentioned that martins used holes in walls and roofs of houses... much like how Starlings in Kentucky will use holes in homes. Tell us about Starlings in California... Are they as numerous in California? Does California also "fight" with Starlings taking over native bird nest sites?

[Steve Kroenke]

Hey Stan,

Thanks for sharing that great news from California! We all appreciate the hard work you, Dan Airola, Ken Buker and other purple martin enthusiats do in helping martins out west.

Though I hope the western martins start nesting in bird houses in larger numbers, I still enjoy seeing martins nesting in natural cavities such as woodpecker holes.

I know starlings are a major problem for martins that nest in natural cavities. However, it appears that martins may nest later after starlings have finished using the cavity. In your area, do find that starlings tend to nest earlier than martins? I have seen in north Florida red-headed and red-bellied woodpeckers nest in late May through August when starlings are no longer actively looking for nest sites; starlings are significant competitors with these woodpeckers for nest sites. Perhaps martins can in some instances still successfully raise young in starling infested areas AFTER the active starling nesting season is over.

Thanks again for the update from California.

Steve

[Linda Reynolds]

That is WONDERFUL news, and thanks so much for the update. I wish you and your team much success in 2010 and the future. You are doing wonderful work.

[Daniel Airola]

I can offer some information on starling status in California, where I have done quite a bit of work on martins. Starlings arrived here as breeders in the early '60s and rapidly increased their population. Doe to suitable agricultural and residential habitat conditions, Starlings attain some of their highest continental population densities in California (too too dissimilar from a two-legged invasive species).

The starling's arrival and increase correlates well with substantial declines in geographic range and numbers, including elimination from lowland areas in southern California and from nearly all of the Central Valley (except the now rapidly declining bridge-nesting population in Sacramento). Martin populations remain mainly in forested areas that support limited foraging habitat for starlings, and have been eliminated from areas that contain good starling habitat. Thus, getting martins used to using starling-resistant nest boxes could open up a lot of nesting opportunity.

There is not a lot of information available on the timing of starling and martin nesting activities in the state. Starlings start earlier in Sacramento, so that the starling's late nesting period overlaps with the early nesting period for martins. Occasionally here, SYs and other late nesting martins will re-use a hole used earlier in the year by starlings, but that is the great exception. We do not see a lot of overt competition in the bridges, possibly because starling numbers are low at most martin colony sites (urbanization also doesn't produce a lot of starling food) and there are so many holes in the freeways from which the birds can choose.

I seldom see direct interactions between martins and starlings - just occasional chasing of one by the other during hole selection in spring.

Thanks for your interest.

[stan kostka]

Hi Larry and Steve,

A bit further up the west coast, here in Washington State, starlings most certainly nest earlier than martins. I've seen starlings here investigating cavities, and acting seemingly on territory, in late February, depending on each year's weather of course. The earliest martins generally show up here mid April, and don't lay eggs until June. I have over the years seen some instances where martins used a nestbox after starlings fledged, I wouldn't characterize this as extremely rare, but certainly wouldn't call it common either, but it does happen . I would say it likely happens much more often during consecutive favorable weather years when martin populations are increasing, and there are not a lot of surplus cavities at some colonies.

And, I really do not know how abundant starlings are in Shelter Cove. They have suitable foraging habitat on lawns and the golf course, but Shelter Cove is a small spot in a huge coastal forested area which does not support starlings. Starlings have never used one of our nestboxes there. The boxes have rectangular SREH, but starlings here in Washington state often get through those entrances.

And here's another thing, I hate to even mention it because I hate to jinx the deal, but, I'm not that superstitious, so here goes. In all the years I have been going to Shelter Cove, I have never seen or heard a single House Sparrow. That's sort of a miracle when you think about it.

Stan