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Archive for August, 2009

Acadia’s annual fall HawkWatch has begun atop Cadillac Mountain; Jenna Dodge will write weekly updates, which I will post here. Here her first “Riding the Winds” report:

As summer fades into autumn, it is accompanied by many important changes like the shortening of available daylight and a drop in temperature. These two key features of seasonal shift are a strong cue for many animals; it may trigger the return to school for humans or the preparation for hibernation for black bears, but for raptors or birds of prey, it means migration.
This annual southward movement is initiated by an abundance of food, temperature, and, predominately, the amount of available daylight. A decrease in the photoperiod plays a key role in prompting certain hormones that signal raptors it is time to get ready for their seasonal journey. To prepare, raptors will consume ample amounts of food to bulk up their fat, or fuel, reserves needed to fly great distances. They can often be observed acting in a very restless manner as if they were itching to get on the “road,” or, in their case, the wind.

Strong gusts of wind from the north help push raptors to their desired destination along the eastern coast; this jagged North American boundary acts as a map for migrating birds and provides key landmarks to keep them on course. Furthermore, updrafts, vertical movements of warm air, form along mountainsides and are very favorable to birds that exploit them for a free ride. Due to this, each year raptors by the thousands fly over Cadillac Mountain, the highest peak on the eastern seaboard, which makes it an excellent site to view their journey. Since 1995, employees of Acadia National Park have watched the sky; recorded the particular raptor species and correlating abundance as the birds soar overhead; and related information to the public. HawkWatch is a vital component in assessing raptor populations throughout the nation, and there are many sites where hawk-watching is performed. Data are submitted to the nonprofit organization Hawk Migration Association of North America (HMANA) and provide researchers with a notion of the health of the population.

Since its inception in Acadia, HawkWatch has entertained numerous visitors with about eleven different species of raptors, averaging about 2,600 sightings per season. We can expect to see a variety of birds of prey atop Cadillac—falcons, accipiters, buteos, eagles, osprey, and harriers, which all possess unique physical characteristics, as well as the ecological and intrinsic importance that we will discuss in later issues of Riding the Winds.

Over the next couple of months, the fall sky will become heavily spotted with migrating raptors, and with your help we may contribute to the pool of knowledge surrounding migration. Please join us from 9 a.m. to 2 p.m. (weather permitting)~200 yards down the Cadillac North Ridge Trail to take part in HawkWatch. Bring your binoculars (the park may provide some if you do not have any) and an eager curiosity for raptors and their splendor.

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Nucella lapillus. Image by Manfred Heyde. This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License.

Nucella lapillus. Image by Manfred Heyde. This file is licensed under the Creative Commons Attribution ShareAlike 3.0 License.

On Tuesday, August 18, 2009, Dr. Peter Petraitis, Professor of Biology from the University of Pennsylvania, will present his research on dogwhelks at Maren Auditorium at the Mount Desert Island Biological Laboratory at 7:30 p.m.  Dr. Petraitis’ talk titled, “Dramatic shifts in shell size of dogwhelks (Nucella lapillus) in Maine over the last century” is part of the Acadia Science Seminar Series, co-sponsored by Acadia National Park, the Mount Desert Island Biological Laboratory, and Friends of Acadia.  The talk is free and open to the public.

A summer resident of Swans Island, Dr. Petraitis has been studying the rocky intertidal zone of Maine since 1981.  His most recent work, done in collaboration with Jon Fisher, Erika Rhile, and Harrison Liu, has shown a 20% increase in the size of dogwhelks over the last century.  Dr. Petraitis and his colleagues studied dogwhelk shells collected by Harold Sellers Colton from 1915-1922 at more than sixty locations around Mount Desert Island and catalogued in the Academy of Natural Sciences in Philadelphia. They compared them to modern populations at nineteen of Colton’s collection sites.  The study team determined that modern dogwhelks found in sheltered locations around Mt. Desert Island had on average 27% longer shells than their predecessors.  Dogwhelks found at exposed collection locations also showed an 8% average increase in shell length, and semi-exposed locations contained dogwhelks with shell length on average 23% longer.  Dr. Petraitis will also discuss several possible causes for this dramatic increase in shell size at his lecture.

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A total of 46 people participated in the 7th annual BioBlitz held at Acadia National Park’s Schoodic Education and Research Center. Both professional and amateur entomologists spent 1,308 hours searching for and collecting insects from 16 orders that have relatively few species in Maine.

Bioblitz participants.

Bioblitz participants.

Institutions represented at the event included: Maine Entomological Society, Maine Forest Service, New Hampshire Department of Agriculture, University of Maine, University of New Hampshire, University of Southern Maine, Illinois State University, University of North Alabama, Texas A&M University, Colby College, and the Carnegie Museum of Natural History. In addition, a taxonomist from the University of Tennessee has agreed to identify the Collembola species not identified at the BioBlitz. (more…)

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Fledging Great Egrets. (CLT, Sarah Island, 2009)
Fledging Great Egrets. (CLT, Sarah Island, 2009)

We had our last day on Thursday, August 6th (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 Terns 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 Tern Census, we reported an estimate of 104 Common Tern nests on the platform off Spinnaker (130 flushed adults X 0.80 estimated nests per adult flushing). (more…)

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Tuesday evening (August 4), the Schoodic Education and Research Center hosted a presentation and conversation with Dr. Robert Brooks on the research he has conducted in the Schoodic region sponsored by the Frenchman’s Bay Conservancy.  Here is a summary of Dr. Brooks’ lecture, Schoodic to Schoodic Wildlife Corridor Initiative: toward a science-based assessment.

The Frenchman’s Bay Conservancy has partnered with Dr. Robert P. Brooks—Professor of Geology and Ecology—of Pennsylvania State University—and various state and federal agencies to conduct biodiversity and landscape connectivity research in the area from Schoodic Point to Schoodic Mountain (known as the Schoodic to Schoodic, or S2S, area).  The ongoing study will inventory and monitor specific habitats and communities, assess ecological conditions, and provide defensible, scientific information for land management.  Results will ultimately help scientists design and conserve wildlife corridors in the S2S area. (more…)

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This past weekend marked my last Saturday and Sunday on the coast of Maine, and it seemed that a great way to wrap up this incredible summer would be to try and get a glimpse of some of the animal life that this state boasts. The original plan was to take the one o’clock whale watch out of Bar Harbor on Saturday. However, I underestimated the draw of one of our only days of blazing sun so far this summer. The traffic into town was nigh unbelievable, and that particular whale watch was completely sold out. Not to be deterred however, I returned the following morning for the eight-thirty whales and puffins tour. Even early on, the day showed promise for being spectacularly fair weather…on land, that is. A brooding fogbank lay over the water, engulfing the Porcupine Islands and blanketing the sea. However, it was my last Sunday on the island, and despite warnings that the risk of sea sickness increases when you can’t see the horizon, I went ahead and boarded the boat. (more…)

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