Boston Harbor Islands Volunteer Waterbird Monitoring Carol Trocki’s Field Notes, week of August 3, 2009

Summary from Thursday, August 6:

We had our last day on Thursday, August 6, 2009. (so this is the last you’ll hear from me for a while because I’ll be busy entering and analyzing data and preparing this year’s Field Season Summary!)

We started our day with a visit to the platform off of Spinnaker Island in Hull, where we had observed an estimated 130 adult Common flushing from the colony on June 10th. Given our timing (approximately 2 months later), it was not really surprising to find no terns remaining in the area, though I expected to see some adults and young still hanging about. It is impossible to know if this is an indication of colony success (everyone is grown and gone on time) or colony failure (somebody came by and ate up all the babies, so why stick around?). Not knowing is of course frustrating, but we do what we can. For the purposes of the Massachusetts Census, we reported an estimate of 104 nests on the platform off Spinnaker (130 flushed adults X 0.80 estimated nests per adult flushing).

Although we didn’t see any Common Terns, we did find a number of Laughing , impersonating Common Terns, on a boat in Hull Harbor – a sure sign that August has arrived and the breeding season has ended.

My main purpose for scheduling a post season trip was to visit the wading colony on Sarah Island in Hingham Harbor. I was hoping that we might be able to gauge nesting effort at the colony site by counting nests at the very end of the season, after the are done using them (limiting our disturbance during nesting), but before winter storms remove them. Alas, our efforts were thwarted by – of all things – pokeberry. If you are familiar with this native species, you will know that it is a fast growing berry producer, beloved by Gray Catbirds everywhere. What you may not know (because I sure didn’t) is that it THRIVES in the bird- -enriched soils of Sarah Island (we nearly lost Carl! -see photo attached). Although I was more than ready to throw up my hands in defeat, Bob and Pat preserved and continued counting the nests as best they could as we made our way back to the boat. In the end we were able to document 180 wading bird nests, or about half those we marked in May. There were still a few unfledged Snowy Egrets in the colony and several juvenile Great Egrets about (see photo attached). In the end, the lesson we learned is that a visit to the Sarah colony site after the first hard frost may be something to explore further….

For those of you interested, Wikipedia mentions Pokeberry specimens 14ft high, so it appears things could have been much worse... As we left Sarah, cursing the pokeberry and exchanging laundry tips for removing pokeberry stains (just leaves, not berries yet, thank goodness) Tim shared some interesting facts about the use of pokeberry in medical research. Although poisonous to mammals, I knew that pokeberry berries were used by Native Americans and others to create beautiful dyes. It turns out that the plant is currently being researched for its anti-viral properties and potential uses in the treatment of viruses like AIDS (http://www.mhhe.com/biosci/pae/botany/botany_map/articles/article_46.html) - who knew?

Other items of note this week include a reported sighting of two fledged American Oystercatcher chicks on Snake Island. We also had a Wilson’s Storm Petrel sighting between Peddocks and Bumpkin on 8/6.

Laughing Gulls impersonate Common Terns, Carl Johnson negotiates pokeberry, and fledging Great Egrets—Carol Trocki