Keenan handles an Atlantic Puffin that has just received both a Field Readable and USGS Bird Banding Laboratory band before it was weighed, measured, and released. This individual can now be identified and monitored in the field by biologists. Photograph by Isabel Brofsky.
A Three-Hour Tour
Seal Island National Wildlife Refuge (SINWR) lies at the outer edge of Penobscot Bay, about 20 miles from Rockland, Maine and six miles from the closest civilization on Matinicus Island. Getting out to this seabird haven is no easy task. Interns, volunteers, and biologists with the National Audubon Seabird Restoration Program, also known as Project Puffin, must first board the Rockland-Vinalhaven ferry for an hour-long journey. When the boat reaches the quiet, small harbor in Vinalhaven, John Drury—son of the late ornithologist Bill Drury—greets you with his boat, fittingly named the Skua. After departing the harbor, John weaves the Skua through the small rocky islands that scatter the eastern coast of Vinalhaven Island. Many of them, including Little Roberts Island, are inhabited by gulls and cormorants and give you a sneak peak of what is to come.
Seal Island’s rocky cliffs and pools attract nesting seabirds and migratory songbirds. All photographs by the author unless otherwise indicated.
As John dodges the lobster buoys that sprinkle the ocean, he points out the birds, geology, cetaceans, and anything related to the local natural history. His passion for the ocean and all its inhabitants brightens up even the roughest crossings of the bay. As you putt closer to SINWR, you start to notice small rafts of alcids on the water and terns hovering over the surface hunting for their next meal. Once the island is in sight, the sheer number of birds becomes obvious. Thousands of terns swirl above the colony on the northwestern point and hundreds of puffins loaf on the rocky boulder berm that surrounds the island. I will never forget the feeling when I first stepped onto SINWR for the first time in 2014. It was breathtaking and it left me speechless. I quickly realized that I would be living in a place still ruled by birds. The five biologists living on the island would be the minority species, a rare phenomenon in today’s world.
The living quarters on SINWR are modest. Each person on the island gets his own tent platform and tarp, which becomes his new home anywhere from two weeks to the entire field season of four months. A small 12-foot by 12-foot cabin is centrally located between the platforms as is a composting outhouse toilet. There is no running water on the island and dishes are washed by hand with rainwater or seawater. Inside the cabin, there is storage for research equipment, a small table for dining, a desk for data entry and management, a marine radio for emergencies and communication between islands, and a small kitchen area with a two-burner propane camp stove. A bath is usually just a swim in the frigid Atlantic but once you get out you can enjoy a seat next to the campfire. Life is simple on the island. It seems like it always has been, and I think this wildness will continue to attract future generations of biologists who learn from the seasoned souls continuing their generous efforts to conserve seabirds and teach others.
A bird blind in the tern colony of Seal Island NWR where puffineers conduct studies on chick diet and read band numbers throughout the nesting season.
The History of SINWR
During the eighteenth and nineteenth centuries, humans exploited seabird colonies along the coast of Maine for the trade of feathers, eggs, and meat. By the early 1800s, the populations of many seabirds, including the Atlantic Puffin, plummeted and puffins occupied only two islands in the Gulf of Maine, nearby Matinicus Rock and Machias Seal Island at the mouth of the Bay of Fundy. Sadly, Matinicus Rock was hit so hard that only a single pair of puffins survived into the twentieth century.
After the extirpation of its diverse seabird colony, SINWR was home to a small fishing camp and today some descendants of its inhabitants still fish the rich waters surrounding the island. However, the island was closed to all activities from the 1940s to 1960s when the U.S. Navy used it as a bombing range. Unfortunately the impacts are still seen on the island and it remains closed to the public due to concerns over unexploded ordinance. Once the bombing ceased, Seal Island’s ownership was transferred to the Department of the Interior but it wasn’t until the U.S. Fish and Wildlife Service and Project Puffin took over management of the island that seabirds began to return.
An Atlantic Puffin returns to its burrow with a bill load of hake. This photo was part of a greater feeding study to track the diet of puffin chicks from season to season.
In an effort to reestablish Atlantic puffin populations, between 1984 and 1989 one thousand 10- to12-day-old puffin chicks were transplanted from Great Island in Newfoundland to artificial sod burrows where they were handfed and raised by biologists living on the island. The hope was that these puffins would return not to their natal colony in Newfoundland, but by becoming familiar with the sights and sounds of their new home on SINWR, would return to breed here instead upon maturation. To encourage the transplanted puffins as well as other roving Gulf of Maine puffins to nest on the shores of the island, Project Puffin’s Dr. Steve Kress used social attraction methods such as decoys and mirrors, which were strategically placed at locations that could be viewed by puffins at sea. This made the island appear like a thriving puffin colony. It wasn’t until 1992—eight years after the first translocations—that puffins first began to breed on SINWR. Similar social attraction techniques also were used to attract Common and Arctic terns, which began to nest on the island in 1989. Since these attraction methods were implemented, the diversity and numbers of nesting seabirds have continued to increase.
|Terns and Gulls
|Great Black-backed Gull
Table 1. A list of the breeding sea bird species and the estimated number of breeding pairs.
Breeding Birds on Seal Island NWR
During the summer, SINWR hosts a diverse suite of nesting seabirds (Table 1). Although research on the island focuses on three alcids—Atlantic Puffins, Razorbills, and Black Guillemots—in addition to Common and Arctic terns, many other birds also nest on the island. In fact, 17 pairs of Great Cormorants—nearly half of all the known pairs breeding in the United States—nest on SINWR. In 2016, all 42 pairs that were confirmed breeding in the United States nested on four islands in the Penobscot Bay Region. This small population in Maine has rightly earned a threatened status from the state. SINWR’s Great Cormorants consistently have been the most productive colony of Great Cormorants in Maine primarily due to efforts of the resident interns to deter Bald Eagle predation, which has been problematic at other nesting colonies.
A more common species breeding on SINWR is the Leach’s Storm-Petrel whose charming purr calls often lull you to sleep. The last census of Leach’s Storm-Petrel on SINWR was in the 1990s when approximately 700 pairs were estimated to be nesting on the island. Other species such as Double-crested Cormorants, Common Eiders, and Herring and Great Black-backed gulls are monitored through an annual census conducted visually from either land or boat, or by surveying a subset of the island that is easily accessible by foot. Other species that are not intensively monitored but breed on the island include Spotted Sandpipers, Common Yellowthroats, Savannah and Song sparrows, and in some years Yellow Warblers and American Black Duck.
Interns head out to the tern colony to conduct productivity checks. They will band and monitor chicks from hatching until fledging to study annual growth and survival.
A Day in the Life of a Puffineer
Biologists, interns, and volunteers working for Project Puffin are affectionately referred to as puffineers. Being a puffineer is no easy task and often involves countless hours in bird blinds, crawling in and out of rocky burrows, and meticulous data collection. For more than two decades, puffineers have been getting up at 6:00 am to set up spotting scopes and clipboards at the same designated location to count the number of alcids, gulls, cormorants, and eiders that are visible in the water or on land. This is appropriately called the “morning bird count.” After the morning bird count, we record the weather conditions including: sea surface temperature, ambient air temperature, wind speed, visibility, cloud cover, and sea surface conditions, all of which are all recorded three times a day.
After the morning data collection is completed and everyone has had a hearty breakfast, we typically head out to the tern colony for our productivity checks. Since terns first started nesting on SINWR, puffineers have followed a subset of Common and Arctic tern nests to determine their productivity—the number of chicks fledged per nest—and to assess chick growth metrics through banding and measuring. At the beginning of the field season when terns begin to lay eggs, each nest receives a unique identification number and the number of eggs in each nest is recorded daily. Once hatching begins, chicks receive a unique nine-digit band issued by the USGS Bird Banding Laboratory so that they can be identified. Every other day, basic morphometric data, including wing chord and mass, are collected to track growth rates during the nesting season from hatching until fledging. Similar studies also are conducted on Atlantic Puffins, Razorbills, and Black Guillemots. However, checking their nests is much more difficult because they nest among granite boulders that border the edge of the island.
The rocky boulder berms that surround the island are home to nesting Atlantic Puffins, Black Guillemots, and Razorbills. The bird blind is strategically placed to observe alcids nesting behaviors.
After checking the nests and chicks, we often move into bird blinds for the next three hours. During these stints, we conduct a variety of activities. Before many of the chicks hatch, most of our attention is focused on reading the bands of the adult birds through spotting scopes. We use these data to monitor nest site and mate fidelity as well as longevity.
Once the tern and puffin chicks begin to hatch we conduct feeding studies. A subset of nests that are close to bird blinds are monitored from the day the first chick hatches to the day all the chicks have fledged. Using binoculars, we observe each nest for a total of 12 hours per week through multiple three-hour long blind stints. When a feeding is delivered to a chick, the observer records the time, the species of the prey item, the size of the prey item, the individual chick receiving the prey item, and the parent that delivered the prey item. This information is valuable because it allows researchers to follow the diets of seabird species through time and provides valuable information to those managing fish populations.
An Arctic Tern delivers a large sand lance to its young chick.
In addition to productivity checks and blind stints, there are a myriad of other activities that are completed only once a week or during a small window of the season. For example, each year we conduct an annual census of nearly all the breeding species. For some species, such as terns, puffineers carefully walk transects across the nesting colony and count the number of nests and eggs. For other species, we use visual counting methods from land or by boat. Visual observations are particularly useful for species such as puffins that do not nest in the open or for species such as Great Cormorants that nest in an area that is inaccessible without severe disturbance. Other research tasks include keeping a daily bird list, conducting shorebird surveys during migration, and conducting dawn to dusk feeding rate studies on puffins to calculate the average number of feedings a chick gets daily. Needless to say, there is always something to keep a puffineer busy.
Birding on SINWR
Although I have birded in Kenya and Tanzania, the Peruvian Amazon and Andes, Mexico, and across the United States, SINWR is one of the most unusual places I ever have been birding. Because SINWR lies at the outer edge of Penobscot Bay, in spring and fall when migrating birds get blown out to sea with a westerly wind, the first land they come across in their efforts to return to the mainland are the islands smattering the coast of Maine. SINWR is unique in that it lies farther out to sea than other nearby islands and its narrow snakelike shape, which runs essentially south to north for about one mile, is particularly attractive to migrating songbirds.
Spring migration on SINWR is rewarding. Unlike the mainland, the lack of trees provides migrating songbirds with few places to land comfortably. Instead, they use the steep rocky cliffs, crevices, and brackish pond edges as their hunting grounds to fuel up on insects for the next leg of their migration. The first migrants to arrive on the island during the first week of May are Palm and Yellow-rumped warblers, Chipping, White-throated, and Swamp sparrows, and Hermit Thrushes. In addition, the first week of May is often the only time during the entire field season when lingering wintering species such as Iceland Gull, Harlequin Duck, and Purple Sandpiper can be seen. By the end of the first week of May, the breeding terns begin to arrive. Often during their first week on the island they are heard and seen courting and flying high overhead for about an hour after dawn before departing far beyond the horizon to the east, only to return the following morning.
A Blackburnian Warbler stops on the lichen-covered rocks of Seal Island NWR.
During the second and third weeks of May, a strong push of warblers comes through the island. Blackburnian Warblers are a favorite as their stunning black and orange plumage contrast with the granite rock boulders. In the past two years alone, I have seen 25 species of warbler on Seal Island. I think my favorite part of spring migration is that you get amazingly good views of nearly every bird. Whether they are canopy-dwelling species like the Blackburnian Warbler, a skulky species such as the Mourning Warbler, or a boreal breeding species such as the Cape May, Tennessee or Bay-breasted warbler, all are forced to forage in the open, allowing for ample time to respectfully study and appreciate.
I have noticed that many species of migrants find a way to fill a unique foraging niche on the island. For example, Black-and-White Warblers, Red-breasted Nuthatches, and Downy Woodpeckers use the steep lichen-covered boulder cliffs and the cabin, as a substitute for trees. Flycatchers often find an elevated boulder to sally for insects over grassy fields or gullies. Northern Waterthrushes bob their way along the edges of brackish pools, thrushes use the open muddy flats and rocky caverns, and warblers jump from rock to rock, often leaping and flitting straight up to catch an insect out of the air. And of course, Merlin and Peregrine Falcons are almost always waiting atop the highest perches for a songbird to make the wrong move.
A Blackpoll Warbler perches on a granite boulder. They are one of the most common migrants on Seal Island NWR and one of my favorites.
Another fascinating phenomenon that I have had the fortune to witness is fallout. Large groups of birds will often land on the island around 9:00 or 10:00 am. This fallout is likely due to the effect of birds returning west after being pushed out over the ocean with overnight westerly winds. The most notable fallout was early in May 2016 when more than 200 White-throated Sparrows covered the grassy area surrounding our cabin.
Shorebirds and Fall Migration
Early in July, shorebirds mark the beginning of the fall migration. Ruddy Turnstones and Short-billed Dowitchers pick their way through the rockweed at low tide and roost among the flocks of terns at high tide. Greater and Lesser yellowlegs frequent the many brackish ponds. Whimbrels march through the expansive fields on the southern end of the island. Semipalmated Plovers and Sanderlings feed on the large flat expanses of algae-covered granite exposed at low tide. Least and Semipalmated sandpipers are a common sight through July and August and if you are lucky, a more unusual peep may be among them. On several occasions, I have observed Stilt Sandpipers, some still in breeding plumage, among the flocks of yellowlegs. More than once, I have flushed dowitchers feeding in the muddy trail in route to my tent. During a blind stint one may look out to sea and observe migrating flocks of shorebirds. My most exciting shorebird observation from a bird blind was a small group of Hudsonian Godwits in high breeding plumage flying low over the open ocean in early July 2015. Early migrating species and postbreeding dispersal bring new songbirds to the islands, including Yellow Warblers and Empidonax flycatchers. Intriguingly, the past two seasons I have observed significantly more flycatchers in fall than in spring and the exact opposite phenomenon with warblers, but I don’t know if this is a regular pattern. It is not uncommon to come across western vagrants such as Yellow-headed Blackbird, Lark or Clay-colored sparrows, or even a Dickcissel.
The lone resident Red-billed Tropicbird flies through the tern colony.
By the end of August and into the beginning of September, a surge of young Baird’s Sandpipers comes through. They frequent the rocky flat sections of the island devoid of any vegetation and sprinkled with brackish, algae filled pools. Additionally, raptors start moving south and often stop on SINWR for a quick snack. The most common species are Merlin and Peregrine Falcon, but seeing a Sharp-shinned Hawk is not out of the question. The past two seasons I have also enjoyed a nice push of Northern Gannets that often gracefully glide across the island in the evening likely trying to catch some of the only remaining thermals of the day. Unfortunately, puffineers are usually off the island by the beginning or middle of September. I have no doubt that given the opportunity to remain on the island through the entirety of the fall migration, we could observe even more species.
One of the most exciting parts about being a field biologist—and birder—with Project Puffin is that you never know what, when, and if a rare bird will show up on one of the islands. I can’t count the number of times that I was walking to my tent, the outhouse, or a bird blind and came across an unusual bird. All seven of the islands managed by Project Puffin have a long history of rarities including Sooty and Bridled terns, Yellow-nosed Albatross, Curlew Sandpiper, Eurasian Jackdaw, Prothonotary Warbler, Plumbeous Vireo, Black-necked Stilt, and Fork-tailed Flycatcher, just to name few. Since 2005, a Red-billed Tropicbird has spent time on SINWR and Matinicus Rock and has become famous in the birding community. It was first seen on SINWR on July 12, 2005, with an additional sighting the following day on Machias Seal Island at the mouth of the Bay of Fundy. In subsequent years, the bird became quite faithful to Matinicus Rock, but in 2009 it moved back to SINWR where it has since been spending its summers under a large boulder when it isn’t trying to fit in with the unwelcoming Common and Arctic terns.
Although most years are not highlighted by mega-rarities, I have been particularly lucky to observe 189 bird species on SINWR in just the past two seasons. During the summer of 2015, rarities included unusual spring records of Forster’s Tern, American Golden-Plover, and Orange-crowned Warbler, a small group of Bohemian Waxwings, Yellow-headed Blackbird, Lark Sparrow, Clay-colored Sparrows and a young Yellow-crowned Night-heron.
The summer of 2016 was especially fruitful, highlighted by a young King Eider, Hooded Warbler, Olive-sided Flycatcher, Royal Tern, White-winged Dove, high numbers of Cory’s Shearwaters, and the island’s first Upland Sandpiper record. And what a thrill it was to see two new state records for Maine. The first was an Ancient Murrelet that John Drury pointed out to me. What a rush it was to see this Pacific alcid among Razorbills! Just when I thought the summer couldn’t get any better, I found a Great Knot mixed in with some Ruddy Turnstones after a morning thunderstorm blew past the island. This bird represents one of only a handful of records for the lower 48 states and is the first for the Atlantic Coast!
I like to point out to birders that what we often consider to be common species on the mainland can sometimes be big-time rarities for the islands. For example, in the summer of 2016, a Turkey Vulture soaring over the island was a huge surprise and had never been recorded on SINWR. In addition, in 2015 a House Sparrow spent several days around the outhouse, which was one of only a handful of times this species has been recorded on the island. One species that I have dreamed about seeing on the island is a Tufted Titmouse, of all things. It is a common feeder bird for many, but to see one fly over open water is a totally different story. Many raptor species, especially buteos, are incredibly rare on the island, presumably due to the lack of thermals over the cool waters of Penobscot Bay. Perhaps my favorite part of birding on the island is that you gain a true appreciation for all birds both common and rare. Over the course of the summer you might only see one House Wren and maybe only a handful of Dark-eyed Juncos. After not seeing a common species regularly for weeks or months on end, seeing just one individual on the island can bring an excitement and unrealized appreciation for that species.
The Future of Seabirds in the Gulf of Maine
It is no surprise that seabirds in the Gulf of Maine are under significant pressure due to warming sea surface temperatures and rapidly changing environmental conditions caused by climate change and anthropogenic impacts (Mills et al. 2013). Over the past decade, Steve Kress, the director of Project Puffin, has noted significant changes in the diet and condition of Atlantic Puffin chicks. Some prey species such as the Atlantic Herring have declined in the diet while others such as haddock, redfish, and butterfish have increased (Kress et al. 2016). In the summer of 2012, large butterfish were common. Chicks often cannot swallow these fish due to their wide, deep-bodied shape, which left many chicks starving. Fortunately, butterfish are not typically a major prey species in chick diet but, if warming sea surface trends continue, it may facilitate a northward shift of their current southerly distribution (Kress et al. 2016).
Kress (2016) also has noted an annual decrease in the growth rate of puffin chicks at nearby Matinicus Rock. These declines are attributed to the annually increasing trends in sea surface temperatures and declining overall primary productivity in the Gulf of Maine (Kress, 2016). To effectively manage seabird populations in this dynamic world, we must gain a better understanding of how climate change and warming sea surface temperatures are interacting with seabird diet in addition to chick growth and survival at local levels.
Using data collected over the past 25 years by Project Puffin and all its dedicated puffineers, I will be investigating these questions through the completion of my master’s thesis as a fellow with the Northeast Climate Science Center at the University of Massachusetts Amherst. I will focus primarily on the Common, Arctic, and Roseate terns, using this long-term data set to quantify how prey composition has changed in chick diets in relation to observed changes in the environment and how these changes may ultimately impact chick growth and survival. In addition to my own research, there are several other students, biologists, and volunteers throughout New England who are researching the best ways to help these seabird populations thrive for decades to come.
- Kress S. W., P. Shannon, C. O’Neal. 2016. Recent changes in the diet and survival of Atlantic puffin chicks in the face of climate change and commercial fishing in midcoast Maine, USA, Facets 1: 27-43.
- Mills, K. E., A. J. Pershing, C. J. Brown, Y. Chen, F.-S. Chiang, D. S. Holland, S. Lehuta, J. A. Nye, J. C. Sun, A. C. Thomas, and R. A. Wahle. 2013. Fisheries management in a changing climate: Lessons from the 2012 ocean heat wave in the Northwest Atlantic. Oceanography 26:191–195.
Additional Online Links
Keenan Yakola is a fellow with the Northeast Climate Science Center, a master’s candidate in the Department of Environmental Conservation at the University of Massachusetts Amherst, and during the summer months, the Supervisor of Seal Island National Wildlife Refuge with Project Puffin. Keenan is also a native of Cape Cod, Massachusetts; some of his first experiences with birds included working with Mass Audubon’s Wellfleet Bay Wildlife Sanctuary, the Cape Cod National Seashore, and local bird bander Susan Finnegan. He has also spent time working with birds in the Peruvian Amazon and Andes, Kenya and Tanzania, as well as several other locations across the United States.