Preliminary Assessment of Breeding Success of 2012 CATE colony on roof of Trident Seafood Building, Interbay. Without sounding too pretentious, I am trying to pull together a starting "guestimate" from many short reports and anecdotes this season, from the Seattle coastline at Pier 91 north to the Locks. Thanks to Joe Apodeca, Scott Atkinson and Ingrid Taylar among others who have made comments.

Terns present in the area from early May at least until the present. Joe Apodeca commented that the colony was completely unsuccessful last year in fledging young. I originally estimated up to 400 Caspian Terns on the Trident roof this May. These could be birds dislodged from the mouth of the Columbia River, Dungeness Spit or the Bellingham water front site. The roof of the Trident is covered with composition and pitched enough that eggs could slowly roll off. Many eggs were photographed on the roof by Ingrid in May. However the substrate is not ideal to make the usual tern "scrape". Predators on the roof include roosting Glaucous- winged Gulls and American Crows, who specialise in rolling eggs away from the parents, either flying off with them, or rolling them on to the ground to eat the yoke. Doubtless, there are rats present and Ingrid reports noisy commotion from the roof sometimes at night. Could there also be a Raccoon or two about?

Of late there are no eggs visible on the roof and only a few pairs may be "sitting". Scott Atkinson recently reported family groups of Caspian Terns in the general area, though not how many. I myself have seen individual terns diving for smelt-sized fish off West Point and carrying them off in their bills towards Trident. But there are not reports of this behavior elsewhere in Seattle. With a successful breeding colony, one might suppose that there would be terns diving in number at the same location. To-day Joe Apodeca reported a new problem - Bald Eagles landing on the roof and carrying off young chicks, which he assumed were terns. As there are probably at least two active Bald Eagle breeding pairs on the Magnolia Peninsula, they must be a considerable threat, both to CATE and to Great Blue Herons.

All in all, it does not look good for Caspian Terns due to poor site conditions and an able group of predators. Therefore a guess would be that only ten to twenty pairs may have fledged any young and even that may be an over-estimate. If any Tweets have other local Caspian Tern sightings that would be helpful, please post

--
David Hutchinson, Owner
Flora & Fauna: Nature Books
Discovery Gardens: Native Plants
3706 Corliss Ave North
Seattle,WA.98103
http://www.ffbooks.net/
206-623-4727