A Common Tern-Around!

During the winter Detroit Audubon members, Jim Bull and Bruce Szczechowski cut and stacked brush, and reworked the surface on protection piers of Wayne County’s bridge to Grosse Ile to make more of the area available for nesting of the State Threatened Common Tern. It worked.

Last year their were 60 nests on pier, this year there are over 170!!! As of the writing of this article (6-3-05) Bruce and Jim have banded 8 tern chicks—they are just beginning to pop. We hope that there will be at least 150 fledged terns from this site. All will chicks will be banded not only with US Fish and Wildlife Service number bands, but color bands so we can tell what year they hatched and what site they were from, and if we can work out, we would like to identify individuals.

After banding, we usually climb up to the balcony adjacent to the bridge operator’s office and observe the terns for an hour or more, taking field notes on their behavior. Of special note on the day we banded the first young, was watching one tern make 5 trips across the river to the area around the DTE Trenton Channel plant, catch a fish and bring it back and feed each of his or her three young. This parent was an incredibly efficient fisherman and got just the right size fish. We counted five trips, five fish and five feedings in 6 minutes! Some parents, probably first-time parents, will bring back fish way too big for their young to swallow. Not this tern, the fish brought back were just the right size and gobbled down by the young almost before the parent had fully landed.

Sadly, the situation on the toll bridge on the north of the island is not as good. That bridge is undergoing repair and the north crib which held the most nests is now 2/3rds covered with a plastic tarp. While there were 250 nests there last year, only about 40 have squeezed in on the 1/3 of the crib that is not covered by the tarp. The bridge owner, however, did a nice job of resurfacing the south crib with smaller gravel and added plastic tubes for young to hide form predators and get out of the sun. There are more nests on that crib than ever, although we have not been able to get an exact count.

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Press Release -
Dramatic Increase in Nests of State-Threatened Common Terns on Grosse Ile Free Bridge.

VOLUNTEERS NEEDED TO HELP SAVE THREATENED COMMON TERN

July 2005 Appeal -

WHAT: Almost all Common Tern chicks recently hatched are being eaten by Black-crowned Night Herons. If chicks are to survive we need volunteer wardens to be on night patrol to chase them off if they come in.

WHEN: Every night in July from 9:30 to 1 a.m., or 1 a.m. to 5:30 a.m.

WHERE: GROSSE ILE FREE BRIDGE

CONTACT: Jim Bull at jbull51264@aol.com or 313-928-2950. Be sure to leave information on when you can volunteer for this patrol. Note: We will train you to do this (we prefer folks who can do this more than once)

Board Member Jim Bull and member Bruce Szczechowski have been studying the Common Tern colony on the Grosse Ile free bridge. The good news is that through Detroit Audubon efforts habitat improvement work has resulted in an increase in tern nests from 60 last year to 180 plus this year!!! (the year before based on work that Bruce and Friends of Detroit River and DTE did, the 60 nests was a substantial increase over the 17 there in 2003).

We have banded over 200 chicks. The problem is that we have lost about 70 to predation. In the last week and a half we have lost all but one chick we banded. We now know the culpirt--two Black-crowned Night Herons. Bruce and Jim have been on Black-crowned heron patrol every night from at least 9:30 p.m. to 12:30 a.m. ( we think most predation happens in this time period, but it certainly can happen later). It would be even better to have enough volunteers to cover the whole night. The terns leave for the night about 10:15 and the heron comes in soon after for its first visit. We simply chase it off. We are looking into other measures we can take to control predation on this state threatened species. If you would be interested and willing to take a shift on this night patrol please let me know. We'll get you acclimated to the task and the surroundings. If you come a second time as we hope you will, you could do it on your own (just so we know you are there and that the night is covered).

If you come early enough, 6:30 or 7 p.m. at the latest you can observe us dong our nest inventory and banding in the colony (Probably from the bridge). There are still a lot of eggs to hatch. If those eggs are to develop into full grown terns, our help will be needed.

When there were 4,000 nesting pairs on Detroit River islands, seventy chicks taken by Back-crowned Night Herons would probably not have had much impact on the population but now that we have only about 300 pairs total (and the 120 on the toll bridge site have not even had most eggs hatch for some reason), every chick is important to the species's survival. --