Kirsti Strieffert wondered...
"What month do the Caspian Terns set up housekeeping on Rice Island?
When do they leave? Is anyone keeping an electronic file of links to
articles and research on the topic, and if so, would you care to share
it with me? I've decided I need to form an opinion on the topic."

This year they began to arrive in significant numbers (hundreds to
thousands) in mid to late April. Nesting began promptly. I'm not sure when
they disperse.

Black Hills Audubon Society has some info and links at this site:
http://www.audubon.org/chapter/wa/bhas/index.htm

Here's the most recent update I have on file, provided by Dan Roby at OSU:

Scott Richardson
Olympia, Washington
salix at halcyon.com

>Avian Predation Project Update
>June 14, 1999
>
>Caspian Terns (nesting population)
>
>Rice Island
>The high and low on-colony counts for the week (June 7th - June 13th) were
>both on June 12th (9,000 and 8,200 terns, respectively). On Sunday
>(6/13), roughly 8,800 terns were counted on the 1-acre area and adjacent
>vegetated buffer. The number of nests w/ eggs or chicks on the 1-acre
>unvegetated area and adjacent vegetated buffer was estimated to be around
>6,000. There are also another 1,150 - 2,350 individual terns counted in
>two satellite colonies outside the fencing on the west end of Rice Island.
>Our best estimate of the number of active nests in the two satellite
>colonies is 1,300. This means that our current best estimate of the total
>number of active tern nests on Rice Island is 7,300. There is still no
>tern nesting anywhere else on Rice Island. There are large numbers of
>tern chicks on the core nesting area, and gull predation on chicks has
>increased noticeable. Gulls have learned to snatch young tern chicks from
>the surface of the colony without landing. We are in the process of
>trying to quantify this activity and will report these results in the next
>update.
>
>East Sand Island
>The high and low on-colony counts for the week were on June 13th (2,256
>terns) and June 8th (991 terns), respectively. On Sunday (6/13), we
>estimated that approximately 844 pairs of terns had nests w/ eggs or
>chicks on the East Sand Island colony. Gull predation on chicks and eggs
>is rare compared to Rice Island. As of Sunday (6/13), a total of 134
>gulls have been shot on East Sand Island, a critical aspect to the success
>of the Working Group's tern relocation effort. This represents less than
>1% of the estimated number of gulls nesting on East Sand Island in 1998.
>
>Caspian Terns (diet)
>
>For this last week, 37% of the fish delivered to East Sand Island (N =
>379) were salmonids, compared to 70% at Rice Island (N = 408). This was
>the largest week-to-week decline (16%) in the proportion of the diet that
>was salmonids for the Rice Island tern colony. Comparatively, the East
>Sand Island terns consumed 7% less salmonids this week compared to last
>week. Year to date, 63% of the fish delivered to East Sand Island (N =
>3,177) were salmonids, compared to 93% at Rice Island (N = 2,786). Gull
>kleptoparasitism rates at the East Sand Island tern colony (0%, N = 382
>deliveries) and the Rice Island tern colony (2%, N = 409 deliveries) were
>similar to the rates reported last week.
>
>Caspian Terns (foraging ecology)
>
>Trapping: We trapped and radio-tagged another 4 terns on the East Sand
>Island tern colony on Monday (6/7). The trapping that occurred on Monday
>lasted a total of 1.5 hours and we observed no predation on tern chicks or
>eggs associated with that trapping event. We did observe chicks being led
>off the colony, presumably by the chicks' parents, at the time that the
>trapping was taking place. These same chicks were led back to the colony
>area within 1 hour of us pulling the traps. Due to the increased mobility
>of chicks, we will not be doing anymore trapping at either colony for the
>remainder of the breeding season. We now have a total of 22 and 30 adult
>terns radio-tagged at East Sand and Rice islands, respectively.
>
>Tracking: Based on data from our fixed telemetry stations at Rice Island
>and East Sand Island, we believe that 28-29 and 14-18 of the radio-tagged
>terns are likely breeders at the Rice and East Sand island colonies,
>respectively. We made this determination based on repeated nighttime
>attendance of radio-tagged birds at one of the colonies. From these same
>data, we estimate that 5-10 of the radio-tagged terns are non-breeders (as
>of June 13th). Off colony observations of radio-tagged terns (based on
>flight telemetry) revealed that most birds nesting at East Sand Island
>(75%, N = 16 resightings) foraged downriver from the island, whereas the
>proportion of resightings of Rice Island terns upriver and downriver from
>the colony was similar (44% and 56%, respectively; N = 41 sightings). For
>the radio-tagged terns believed to be non-breeders, all resightings were
>downriver of Rice Island and only one resighting was upriver of East Sand
>Island (N = 8 resightings). Of the downriver resightings of terns nesting
>at Rice and East Sand Island, 22% and 50% were outside the estuary,
>respectively. There were 5 (12% of total resightings) and 2 (12% of total
>resightings) resightings of terns in Willapa Bay for terns nesting at Rice
>Island and East Sand Islands, respectively. Foraging of terns in Willapa
>Bay, especially by terns nesting at Rice Island, is a completely new
>finding that underscores the value of the radio-telemetry study. To
>increase our sample size we have decided to conduct 3-4 radio-telemetry
>flights per week for the remainder of the month. Flights are scheduled at
>low tide in an attempt to maximize our off-colony resightings of
>radio-tagged terns.
>
>
>Introduced Predators
>
>No new predator activity has been observed at either tern colony over the
>last week.
>