The cabin we are going to call home for the summer.

Finally, after weeks of anticipation and planning, we (Julia and Katie) have arrived at the island we are going to call home for an entire summer. Our island is called Ship Island, and it lies in Blue Hill Bay, Maine, just a few miles off shore. At just 11 acres, the small island will be called home to not just ourselves, but to a variety of various song birds, sparrows, and seabirds. Our focus, of course, will be on the seabirds, and we are looking forward to a wonderful summer with them.

May on the islands provides a fantastic opportunity to witness the migration of birds. As islands along critical oceanic migration routes, the Refuge’s islands are essential to providing migrating birds a place to refuel and refresh. For the biologists, it is an exciting time to witness new species and observe them closely as they forage voraciously in trees and shrubs just feet away.

Northern Parula from the back window.

Like Petit Manan and other islands, Ship Island has been privy to sundry migrants: 72 in total at the close of today. It seems that nearly every morning we wake up to a new bird song. This morning, it was the Bobolink with his “R2D2” voice.

Bobolink singing his “R2D2″ song in front of a tern blind and West Barge Island

But the migrants are not the only exciting birds we see here – shorebirds flock to our sandy beaches, scouring the rack line for tasty morsels as they probe incessantly with their long bills. Lately we have been seeing up to 50 Black-bellied Plovers, still in the process of molting into their striking summer plumage. Others have included Least, Semipalmated, and Purple Sandpipers, Ruddy Turnstones, Dunlin, Willets, Whimbrels, Short-billed Dowitchers, Greater and Lesser Yellowlegs, Semipalmated and Piping Plovers.

Until next time,

Julia

Petit Manan Island (on one of the few sunny days so far)

Andrea and I (Jordan) have been on Petit Manan Island (PMI) for a little over a week now, getting the island ready for the seabird breeding season. Although the weather has been rather wet and dreary, we’ve put up our observation blinds from which we can watch the Common and Arctic Terns that nest all over the ground, as well as the Alcids (Atlantic Puffins, Razorbills, and Black Guillemots) that nest in rock and sod cavities along the perimeter of the island. There are not many seabirds yet—the terns are still arriving (we’re up to about 500 now), and they only land on the island at night and in the early morning, and the Alcids are just scoping out burrow locations. But luckily for us bird nerds, there are TONS of migrating songbirds stopping to rest and refuel on PMI. We’ve seen over 50 bird species so far, including many warblers, thrushes, and sparrows that are moving through on their way to their breeding grounds. We’ve included photos of some of the migrants we’ve seen so far, and we’ll keep you posted as the seabirds settle in!

Black and White Warbler

Eastern Bluebird

American Redstart

Magnolia Warbler

2013 Bird List (so far)

It seems fitting to conclude this season’s blog with a photo of a young male Rusty Blackbird caught here on October 13.  Among other challenges, habitat loss has played a large role in the precipitous decline of this and many other species, underscoring the importance of public lands like wildlife refuges in maintaining and enhancing vital ecosystems across the country.

Below are some highlights from the past week:

Savannah Sparrow

Tennessee Warbler

“Yellow” Palm Warbler

Yellow-breasted Chat

Fortunately for us, ageing Myrtle Warblers is fairly straightforward, as this species tends to show obvious molt-limits.  Molt-limits are simply differences in the appearance and structure of feathers due to the different times at which they were grown.  In the wing-spread of the Myrtle Warbler below, the difference between the recently molted, fresh alula covert versus the pale middle alula indicates that this is a young bird…

…and the lack of a difference between the same feathers on a different bird below indicates that this is an adult (this is the wingspread of the adult male pictured alongside the female in the first photo above).

Speaking of molt-limits, Red-eyed Vireos can show some pretty dramatic differences between feather generations as well.  Below is a young bird that had a rather limited molt compared with most of the other vireos we have processed.  Note the retained outer greater coverts – most of the hatch year individuals we have seen have molted these completely.  The Red-eyed Vireo is noted for producing multiple clutches per season, so it may be that this individual hatched later in the summer and did not have time to molt as extensively as birds that hatched earlier.

In addition to the increasing numbers of Myrtle Warblers, we have seen more White-throated Sparrows on the move as well.  Like Myrtle Warblers, these sparrows are relatively short-distance migrants.  They abandon boreal breeding grounds in Canada to overwinter in coastal/southern U.S., as well as northeastern Mexico.  Unlike Myrtle Warblers, there is limited dichromatism between males and females, and identifying the sex of an individual is generally impossible outside of the breeding season.  Pictured below is a young bird making its first foray south.

We typically catch more Golden-crowned Kinglets here than their Ruby-crowned counterparts, so it was a treat to have been visited by this young male Ruby-crowned Kinglet.  This is a species that shows marked dichromatism between the sexes, as males are characterized by the eponymous red crown that is sometimes used to intimidate rival males in territorial disputes.

And finally, a photo of Bear Cove, about 200 meters due west of our banding station.

Being stationed on a peninsula can result in some pretty ‘birdy’ days, as migrants funnel down its length in search of food.  We’ve already banded 100 or more birds on a couple of days, and if previous years are any indication, we’ll likely be in for more during this period of ‘peak passage’.

The sun is shining and the weather is sweet, at least for today. The sun gives us energy to run our computer and acoustic devices.  Since the acoustics get priority over the computer, we have had to wait a couple weeks for a good sunny day to fully charge our computer, thus post a blog.  It keeps us in our toes!

The past few weeks have been spectacular.  Only a few days ago, we had some surprise visitors to our banding site: 300 harbor seals! All of which were searching for food, floating around, and calling to each other.  We are so lucky to be living on such an amazing island, seeing some beautiful scenery and working with some really cool birds.  We have gone on epic adventures exploring the island and we have holed up in our sleeping bags eating PB&Js and  reading novels from action adventure, to fantasy, to hiking the Appalachian Trail and more.   Of course we are also working, trying to catch as many birds as we can.

To date we have caught over 450 birds in 32 banding days.  That’s pretty good considering we are only running 14 nets and many days we have to close early because of wind and or rain.  Over the past couple weeks we have been getting some late warbler migrants consisting mostly of Blackpoll Warblers (BLPW).    Since we have been seeing so many BLPWs we have noticed some remarkable variations in their condition.  To explain, one of the measurements that we record on all birds caught is the amount of fat they carry, fat score.  Blowing to separate the feathers we rate the amount of fat filling their furculum, a hollow at the top of the breast.  Fat appears yellow to orangish.  Most birds we have caught have a fat score from 0-1, meaning they have no fat up to fat lining the furculum’s sides.  Recently, the majority of BLPWs we catch score from 2-5.  A bird with a fat score of 5 has fat bulging from the furculum and pouring over the sides of the breast all the way down covering the abdomen!  These birds are carrying up to 25% of their body weight in fat.  The reason for so much fat is that they are gearing up for their nonstop flight to South America for the winter.

Some of the highlights that we have found in our nets are Gray Cheeked Thrush, Bicknell’s Thrush, Blue-headed Vireo, Rusty Blackbird, and Palm Warblers.  We have also been spotting Baltimore Orioles around the house.  A Brown Thrasher stopped over at our banding site yesterday, pretty cool bird if you ask me!  Cross Island is amidst the northern most portion of their range.

Part of what enables this species to winter at such high latitudes is their ability to digest bayberry and other waxy fruits, though they still enjoy a tasty and nutritious invertebrate when available.

We’ve also seen a moderate swell in vireo numbers over the last few days, with a nice mix of both Red-eyed and Blue-headed Vireo (below) flocking-up with other migrants.  Vireos are closely related to Shrikes, and one of the characteristics they both share is a somewhat menacing hooked bill, which aids them when feeding on fruits, invertebrates or (in the case of shrikes), small vertebrates.

And we finally had our first Baltimore Orioles pass through this week…pictured below is a hatch-year female.

Many passerines show similar patterns of molt, and as with the hatch-year Black-throated Blue Warbler discussed in our September 5 post, this female had a good degree of contrast between older juvenal feathers and newer, recently replaced ones.  More often than not, this indicates a young bird, as the adults undergo a complete molt and do not show marked differences in feather aspect.  Below is a closer look at the wingspread of this young female oriole.

Known as ‘molt-limits’, these differences in feathers allow bird banders to accurately assign individuals to age-classes, and one of the leading figures in understanding this phenomena is Bob Mulvihill (below, with a ‘Yellow’ Palm Warbler).  Bob’s yeoman work on molt, as well as a devotion standards rarely matched has equipped a generation of North American banders with the tools necessary to collect accurate, robust data.  It goes without saying that we were honored and delighted to have been visited by he and his wife Pam on Saturday (Sept. 22).

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…and as it likely will be, we are thrilled to welcome Jordan to the crew this week.  Jordan has worked extensively on refuge islands, playing an integral role in re-establishing and protecting threatened and endangered seabird colonies, among other initiatives.  Here she is extracting a Blackpoll Warbler, one of her favorite landbirds.

We were also ecstatic to be visited by a rarity for this region.  On Sunday (Sept. 16) we processed this hatch-year Clay-colored Sparrow.  These are birds that breed in the central portion of Canada and the U.S., and are infrequently encountered this far east.

Another rarely encountered species here, albeit of the shorebird variety, was this American Golden-Plover (bottom individual in photo below).  These birds nest in Alaska and northern Canada, and following the breeding season they generally stage in eastern Canada before departing on a nonstop flight of roughly 4000 km to South America.  Here it is pictured with the bigger (and more common for this area) Black-bellied Plover.

A fairly common shorebird encountered around the refuge during migration is the Semipalmated Plover, pictured here hopping from its saltwater bath.

Like the Semipalmated Plover above, the Semipalmated Sandpiper (below) is named for the partial webbing between the middle and outer toes.  While both species forage along shorelines, and are thus colloquially termed ‘shorebirds’, they are taxonomically assigned to different families.

Another common sandpiper around the refuge this time of year is the Least Sandpiper.  These birds are fattening-up on abundant invertebrates as they move to their wintering grounds that can be as far south as Chile.

Shorebird tracks

Switching gears back to our landbird friends, the Nashville Warbler has a rather protracted migration, with numbers thinning out by mid-October.  This adult male is most likely on his way to Central America for the winter.  Given that he is an adult,  he has certainly made this trip at least once before, and hopefully he will have another successful voyage this year.

While perhaps not a true vagrant, this young female Prairie Warbler that was banded yesterday was certainly a surprise for us.  Prairie Warblers are not typically found this far north in Maine, though they are known to breed in the southwest portion of the state.  They are a bird of early successional habitats, such as pastures and clear-cuts, and this particular individual may have felt at home foraging in the grassy field near our banding station.

This past Thursday (September 13) was an exciting day as well, as we were visited by two Connecticut warblers.  These warblers are typically very retiring, and are known to be a hard species for birdwatchers to find.  They breed in the boreal region of Canada and portions of northern Minnesota, Wisconsin and Michigan.  Though their wintering range is not well known, evidence suggests they engage in long transatlantic flights to Amazonian South America, similar to the Blackpoll Warbler we discussed previously.  Pictured here is an adult female.

Less surprising, but just as delightful, was this sharp-looking hatch-year Swamp Sparrow.  In one of our earlier posts we alluded to the fact that birds can often be aged by the appearance of their various feathers. Normally we look at the wing feathers to garner clues as to an individual’s age, but for this species we can also look at the area between the eye and the upper bill (known as the lore).  Hopefully you can see some yellowish or buffy tones on this bird, which is characteristic for a young bird at this time of year.  Adult lores exhibit more of a steely-gray appearance.

And of course, feather color can often tell us what gender an individual is.  In the Red-breasted Nuthatches below, the black crown of the male is unmistakable when contrasted with the blue of the female below it.

Just as it does for us, color plays a pivotal role in the lives of birds, whether it be for mate attraction, territorial defense or camouflage. There are nearly 10,000 species of birds worldwide, and the myriad plumages found in this incredible group of animals is breathtaking.   Pictured below are a Brown Creeper and a Black-throated Green Warbler, representing two extremes in the avian color spectrum.  The cryptic plumage of the Brown Creeper helps keep it hidden from potential predators while it creeps along tree trunks in search of food.

Among the many benefits of working along the Maine Coast is having some great views of Bald Eagles.  This was a species that up until 1995 was listed as endangered, so it is always a treat to see them – whether they are simply scavenging fish or making off with a Common Eider.

The American Goldfinch is a common backyard bird, and if you’ve kept feeders you’ve likely had some good views of these beautiful birds.  This male is currently molting out of his bright yellow breeding plumage and will soon be sporting a more subdued, grayish look.

Another common backyard bird, particularly at winter feeding stations, is the Black-capped Chickadee.  These hardy little birds remain at some pretty high latitudes during winter, and can survive some incredibly harsh conditions.  One of the ways they stay warm through cold winter nights is by huddling together in tree cavities.

A bird that cannot survive cold northern winters is the Ruby-throated Hummingbird, and this little female (who weighed 3.4 grams) is on her way to the tropics.  It is hard to believe that some individuals of this species will fly across the Gulf of Mexico on their annual migration, a trip covering over 500 miles of open water!   As we discussed previously, birds engaging in these marathon flights put on large reserves of fat, and we have seen some hummingbirds nearly double their bodyweight before heading south.

Not all of our encounters are of the avian variety, and we sometimes have to watch our step around the banding station so as not to disturb these graceful smooth-green snakes.  They blend in well with their surroundings as you can see, and eat mainly spiders and insects.

Thus far we have caught over 800 individual birds of 40 different species.  Migration numbers typically peak here during mid-September through early October, so we expect our daily volume to increase dramatically in the upcoming days.