Am forwarding a fascinating email from a customer of F&F via the Pacific Seabird Group. My only comment would be whether having breeding colonies expand in our area is a good thing or not. What impact would they have, for example, on young salmon stocks locally, from April through July? DH

--
David Hutchinson, Owner
Flora & Fauna: Nature Books
Discovery Gardens: Native Plants
3212 W.Government Way
Seattle,WA.98199
http://www.ffbooks.net/
206-623-4727




Date: Fri, 17 Jul 2009 11:17:18 -0700
Subject: Re: CATES
From: daniel.roby at oregonstate.edu
To: flora.fauna at live.com
CC: Jessica.Adkins at oregonstate.edu; daniel.roby at oregonstate.edu





Re: CATES


David,



Thanks for clarifying your key questions and sorry for not responding earlier to your original email.



It is very likely that Caspian terns transporting fish in their bills in Puget Sound during early May were doing so for the purpose of providing courtship meals to their prospective mates. We have never seen Caspian terns feeding chicks that early in the season at other colonies that we have monitored in coastal Washington. This may or may not mean that there is an incipient colony nearby; some courtship meals are transported at least 50 km from where they are caught to where the mate is roosting or prospecting for a nest site. Sometimes courtship meal are exchanged at sites where there is no suitable nesting habitat, and I would assume that these terns are seeking to form a pair bond before selecting a site to dig a nest scrap and lay their eggs. At the Caspian tern colony at Dungeness Spit, for example, the first egg was seen on the colony on May 10 in 2004 and on May 8 in 2005. In most years the majority of egg-laying by Caspian terns nesting on colonies in coastal Washington occurs in late May, but some late nesters or re-nesters can lay as late as July.



Assuming, for the sake of argument, that the Caspian terns that you saw transporting courtship meals were intending to nest at their destination, there may have been an incipient Caspian tern colony on a warehouse rooftop on Harbor Island. During our aerial survey of Puget Sound on July 2, no Caspian tern colony was found on a warehouse rooftop on Harbor Island. Although a few Caspian terns were seen loafing on rooftops on Harbor Island, and there are some gulls nesting on rooftops there, no Caspian tern breeding colony was found, and it was too early for young to have fledged and left a rooftop colony. This does not prove that there isn?t a tern colony on Harbor Island (a small colony further from the coastline might have been missed), nor does it prove that no colony existed there earlier this season and failed. There is quite a history of Caspian terns nesting on warehouse rooftops in the Puget Sound Region, including Bremerton Naval Shipyard, Tacoma Yacht Club, Bellingham Cold Storage, and Seattle Pier 90. We have been told by USDA-Wildlife Services that the large Caspian tern colony (several hundred nesting pairs) that was formerly spread over the rooftops of 3 adjacent warehouses in the Bremerton Shipyard has been eliminated by hazing the birds, and no Caspian tern nesting has occurred there in 2008 or 2009. The terns that nested at this former colony likely dispersed to alternative colony sites in the Puget Sound Region, and may have been the source of the Caspian terns that you observed. If a colony did form this season on a warehouse rooftop on Harbor Island, it is also possible that the owners of the property either hazed the birds themselves or hired Wildlife Services to do it.



In addition to the Caspian terns that formerly nested at the Bremerton Naval Shipyard, some of the terns you observed may have been from the large breeding colony on Dungeness Spit in Dungeness NWR. This colony, which originally formed in 2003, has experienced increasing predation pressure from terrestrial mammals, especially coyotes, which have been observed on several occasions in the colony consuming tern eggs. This year, the Caspian tern colony at Dungeness Spit appears to have completely failed due to nest predation late in the incubation period (latter part of June). In 2007, this colony supported more than 1,100 nesting pairs, the second largest breeding colony of Caspian terns on the Pacific Coast. It is not clear where these terns will try to nest next year.



A warehouse rooftop in the Elliott Bay area is certainly a potential site for a Caspian tern colony to form, if not this year, then perhaps in 2010. I guess the site would only be inappropriate if the owners of the warehouse are determined not to have their warehouse used as a seabird nesting site. Usually, Caspian terns take their cues on potential colony sites from where gulls are nesting, so rooftops where gulls have nested in the past are sites that warrant the most searching for nesting Caspian terns. Following terns that are transporting courtship meals might be the best way to locate an incipient tern colony; if adults are observed carrying fish in their bills in late June or July, that would likely indicate a tern colony where at least some eggs had hatched and adults were feeding young.



In my view, it would be optimal if an old flat-roofed, gravel-topped warehouse somewhere on the Seattle waterfront were identified as an appropriate site for colonial waterbirds, like Caspian terns and glaucous-winged gulls, to nest. The owners of the warehouse would obviously need to agree to this, and not allow people to access the rooftop to haze the birds. If such a warehouse could be identified, then social attraction (decoys, sound system) could be employed to encourage Caspian terns to nest on the rooftop. Our group could loan the use of the decoys and sound systems for this purpose, if folks in the Seattle area can secure the site. This would presumably help solve the dilemma for Caspian terns that formerly nested at Bremerton Naval Shipyard and Dungeness Spit.



Hope this helps,



Dan





Daniel D. Roby, Professor

Oregon Cooperative Fish and Wildlife Research Unit

Department of Fisheries and Wildlife

104 Nash Hall

Oregon State University

Corvallis, Oregon 97331-3803

Phone: 541-737-1955

Fax: 541-737-3590

Email: daniel.roby at oregonstate.edu













On 7/15/09 9:27 PM, "David Hutchinson" <flora.fauna at live.com> wrote:



Dan, I hate to bug you, but I also don't want our observations to get lost in the shuffle. Regarding my previous email about CATES on Puget Sound, the key question for us is : what does it mean when the terns are seen flying several miles with fish in their bills in the first days of May? Are they feeding young? Is it courtship feeding for a Seattle colony? Does courtship feeding begin some weeks before nesting and they fly elsewhere than Elliott Bay to nest? Could it be attempted breeding at an inappropriate location? I know this is all rather hypothetical, but the answers would be educational for a bunch of local observers. Thanks, Dave



--

David Hutchinson, Owner

Flora & Fauna: Nature Books

Discovery Gardens: Native Plants

3212 W.Government Way

Seattle,WA.98199

http://www.ffbooks.net/

206-623-4727







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