Hurrah! People are reading the blog after all!

Well, I know it’s summer, and many of you have other (better?) things to do than read a blog largely about dead birds. But the rare “Live Bird Quiz” I posted on Tuesday brought some long-time SEANET devotees out of hibernation. John Stanton, Helen Rasmussen and Libby Rock correctly identified the flock of loafing gulls as Bonaparte’s gulls in non-breeding plumage. Libby wrote, “Ooooh, so sweet! Bonaparte’s Gulls, in winter colors? One of my faves – and what else has that lovely spot on their heads?” That question got me thinking, what else DOES have that lovely spot on its head? Well, let’s see…the candidates would be Little Gulls and Black-headed Gulls. The aptly named Little Gull is the Smallest Gull in the World. They are primarily a Eurasian species, but a few pairs were discovered nesting in North America in the 1960s. They are now by no means a common sighting, but show up consistently from year to year in winter along the East Coast.

Side by side: Bonaparte's (left) is larger, with a heavier bill and less of a black cap than the Little Gull (right). (photo by T. Riecke)..

Complicating, or maybe assisting, attempts to tell them apart from Bonaparte’s Gulls, the two species will flock together, so seeing a Little Gull in among the Bonaparte’s is not out of the question. When seen side by side, the Little Gull will appear noticeably smaller than a Bonaparte’s and have more of a black cap, in addition to the black “ear spot” they share with Bonaparte’s. In flight, non-breeding adult Little Gulls are distinctive for their dark underwings (Bonaparte’s, like most gulls, show a pale underwing with black wingtips.)

Non-breeding adult Black-headed Gull. Of note: red legs, red bill.

The other possibility, the Black-headed Gull, shares the same sort of background with the Little Gull: another European native, records of the species in North America increased throughout the last century, and the first record of North American breeding by the species came in 1977. Accounts differ on what sort of company they keep; Sibley says they “often consort with Laughing and Ring-billed Gulls,” while Cornell’s Lab of Ornithology reports that they frequently flock with Bonaparte’s Gull. I suspect both are true. So, how to tell a Black-headed from a Bonaparte’s? Non-breeding adults of the two species are quite similar, but the Black-headed will show dark red legs, and a heavier, red bill, as compared with the pink legs and black bill of the Bonaparte’s.

The last word on the pale gull. At last.

OK, so another ultra-birder pro extraordinaire has weighed in.  Blair Nikula also answered my desperate email plea for guidance, and wrote:

“Well, I agree it’s a large gull of some sort, but I don’t think I would venture beyond that!  At least not based upon just the photos.  I think the bird is more likely to be extremely bleached rather than leucistic.

(I’ve never seen a gull, leucistic or otherwise, that had white legs.) The bill shape would argue against Iceland, but is consistent with Herring.  And, of course, the odds heavily favor Herring as well.

That’s my two cents worth.”

The only issue is that this bird was reasonably fresh, and could not have been dead on the beach all that long in the heat of the summer. Thus, there could not have been all that much time for the carcass to bleach out. What’s more, we don’t typically see this degree of leg bleaching even in very decomposed carcasses that have sat out for some months. Very mysterious. Alas. For official recording purposes, we will err on the side of caution and record this as a Herring Gull. The odds are against Iceland Gull, and all we can really play here are the odds.

And now, for a completely unrelated photo. Anna Bass, who Seanets in Maine, sent this picture to us, and I love it! While not dead birds, these guys are just so cute! In a very professional, sciency way, as I told Anna. I know they aren’t dead, but want to try your hand at an i.d. on the species here? Anyone?

Gulls loafing about in Maine. (photo by Anna Bass)

 

More on the pale gull, and some summer diversion

After an email plea from your SEANET blogger, super-birder and gull pro Steve Mirick most generously offered his thoughts on our white gull. Steve wrote, “Gulls are notoriously difficult at this time of year due to extreme feather wear on some individuals.  I believe that white feathers, especially will wear down pretty fast…The lack of any noticeable dark pigmentation in the flight feathers of the left wing would support the possibility of Iceland Gull.  I can’t say about the measurements.  The bill looks a tad thick for an Iceland Gull, but that may just be an appearance due to the lack of head feathers!
Although Iceland Gulls are rare in the summer, they do occur from time to time.  There had been one in NH up until a couple of weeks ago, and may still be around.”

Indeed, Steve himself spotted the Iceland Gull hanging out in Hampton, NH the first week of July. Up in Maine, where our Bird A was found by Helen Rasmussen. Helen follows the eBird alerts for Maine, and reports a handful of sightings of living Iceland Gulls made by birders farther north in Lubec, and at Acadia National Park. One was spotted in Scarborough, about 10 miles south of Helen’s beach, back in late May. So the species, while certainly not at all common in New England in summer, is not unheard of. Of course, neither are leucistic (pale) Herring Gulls. But, with Steve Mirick saying our Bird A could be an Iceland Gull, your blogger feels a great deal more comfortable calling it so. At least until someone else violently challenges the i.d.

Diamondback Terrapin tracks on Cape Cod. (photo by R. Jordan)

As for today’s diversion, with a soul-deadening heat wave gripping most of SEANET territory, I am sure many of you readers are not rushing out to the beach today. So I shall bring some beach sights to you. Dick Jordan, who walks for us on Great Island in Wellfleet, MA on Cape Cod, sent some very cool pics. He found some odd tracks on his beach, and after review by Mary Hake of the National Parks Service, they were determined to be Diamondback Terrapin tracks! Dick also spotted a beautiful breeding pair of American Oystercatchers. Fantastic!

American Oystercatchers at home in Wellfleet, MA. (photo by R. Jordan)

Back to business! (Dead Bird Quiz answers)

Your SEANET blogger is off to meet Dr. Julie Ellis’ baby today, but first, I cannot shirk my duty to the DBQ. I was shocked, shocked! to discover that no one had proffered any answers whatsoever on this quiz. Is anyone even out there?!

Well, despite the lack of response, I shall fling my thoughts on these carcasses into the void.

Juvenile Iceland Gull: our Bird A?

Bird A is a true stumper. As I see it, there are a few options: Glaucous Gull, Iceland Gull, and some sort of albino/leucistic Herring Gull. Glaucous Gulls are bigger on every score than our Bird A, and aside from that, the youngsters of that species tend to have a brownish coloration on a generally white base, not nearly so white overall as our specimen. In terms of size, this could be either a Herring Gull or a Iceland Gull. So, how can we make this determination? Well, the bill is on the large side of the range for Iceland Gull, and seems a bit heavier/stockier than a Iceland Gull’s. Still, that is rather subjective. Juvenile Herring Gulls and Iceland Gulls both have a generally pink bill with a black tip, so that doesn’t help much.

Our Bird A appears to have white legs. While beached carcasses can bleach out in the sun, we don’t usually see complete bleaching of all pigment, so that feature tends to push me toward the idea that this is a leucistic or albino Herring Gull. Albinism results when the pigment melanin is not produced. In complete albinos, this means even the eyes and skin lack any melanin, and generally look pink where the blood vessels show through the unpigmented tissue. Colors not produced by melanin (many yellow pigments, for instance) can still occur in an albino. Leucism, on the other hand, is a failure of pigment to migrate to places where it normally occurs. This applies to melanin as well as other pigments, so leucistic birds may lack all pigment in part or all of the body. If we take the white color of Bird A’s legs as a real phenomenon, and we know that the legs in both Herring Gulls and Iceland Gulls are normally pink, then that would tend to indicate a leucistic bird who retained pigment in the bill. It’s impossible to know what color the eyes are since they are closed in the mask of death. Also not helping matters is the advanced state of dishevelment in this bird. Iceland Gulls and Herring Gulls are often differentiated by “expression,” an amorphous assessment of head shape, bill proportions and the general attitude of the bird. This one is dead and missing most of its head feathers, so it’s hard to say whether it would have resembled the rounded, innocent looking head of an Iceland, or the scheming, fierce head of a Herring Gull.

The final, confounding factor is that, while some signs point to leucistic Herring Gull, such birds usually retain some paler “ghost” version of their normal plumage. So, while the overall color of the leucistic Herring Gull pictured here is whitish, there is still a substantial brown color to the primaries (which would normally be dark brown or black). Our Bird A doesn’t seem to have any of that retained brown pigment in what’s left of the primaries.

So, sigh. I fear this has been nothing more than a diverting argument with myself. I need to move on to Bird B.

Bird B has lobed toes! Or did, once upon a time, and still has some shreds of them left. So, that means Bird B is a grebe. Not much to this bird beyond a puff of feathers, so going simply by the tarsus length, which is small for a grebe, my best guess is that this is a Pied-billed Grebe. On this one, bird expert Dick Veit agrees with me, which is a relief and is how I will end this fruitless discourse.

Leucistic Herring Gull: is that you, Bird A?

Live Baby News supplants Dead Bird Quiz!

Look at that baby! Iris Olivia arrived on Tuesday.

The long wait is over, and your SEANET blogger can finally announce that our own Dr. Julie Ellis gave birth on Tuesday afternoon to 7lb 10oz baby, Iris Olivia Hoffman! Mom, Dad and Iris are all happy and healthy, though happiness is always difficult to assess in a two day old.

For those of you uninterested in babies, and who only want to know the DBQ answers, you must remain in suspense for some time more. And I hope this will give SOMEONE an opportunity to make a guess. Is anyone out there?!

Anyway, CONGRATS to Julie and Andy on this good-looking baby girl; we expect she’ll be out banding gulls by next season!

 

Dead Bird Quiz

It’s difficult to think straight on the second day in a row of grotesque heat and humidity. I can muster just enough mental acuity to post this dead bird quiz. Here’s hoping that by the time I have to provide some answers, my brain will be less addled by weather.

Bird A, dorsal view. Found by Helen Rasmussen in Maine.

Close-up of Bird A's sodden profile.

Bird A, found by Helen Rasmussen in Portland, Maine on July 2nd. Culmen length is 50mm, wing chord 33cm, tarsus 54mm. Thoughts?

 

Bird B was found back in March by Maggie Komosinski in Rhode Island. This blast from the past is likely a fond wish for the weather of late winter as I sit here sweltering.

Bird B (or what's left of it). Found by Maggie Komosinski in Rhode Island in March.

Gleanings from our readership

We are so very pleased, here at SEANET, when those not formally enrolled as Seanetters read our blog and offer their thoughts and compliments or critiques. This past week, we received two comments from readers, both of substantial enough substance to share with you here.

Debris from the beach detailed in the Flotsam Diaries blog.

The first comes to us from Harry, a blogger in Saco, Maine, who has undertaken quite a substantial monitoring endeavor on two sections of nearby beach. He records and collects all human-generated debris in those areas, and has been sharing his findings over the past year on his blog, The Flotsam Diaries. Harry wrote to note that the Hooksett sewage discs have made it to Saco, and he has been tracking and mapping the public reports of the discs’ travels. I know that our SEANET blog readers have many common affinities and interests as readers of The Flotsam Diaries, so check it out–I have been quite impressed with the thoroughness and extent of Harry’s project. More confirmation of the value of citizen science!

The second gleaning from our boards is a bit of publicity for a new book of interest to all lovers of the coastal environment, and most particularly our Massachusetts friends. Author/photographer Ethan Daniels, who spent boyhood summers swimming, snorkeling and sailing in both fresh and marine waters on the Cape, has a book out entitled Under Cape Cod Waters, full of striking and genuinely unique perspectives on the aquatic denizens of the Cape. You can see a slideshow of selected images at Daniels’ website, and for those of you in the neighborhood, Daniels will be speaking about his book at several Massachusetts venues in the upcoming weeks; Daniels’ publisher provided us with the schedule:

“On July 27 at 6PM, he will be speaking at the Boston Public Library’s Central Branch, in an event open to the public. We invite the public to join us in listening to Ethan’s talk and to be submerged in fascinating underwater photography from local waters at the Cape Cod Museum of Natural History on July 28 at 7:30pm and at the Woods Hole Public Library on August 1 at 7:30pm, an event co-sponsored by Eight Cousins bookstore in Falmouth. These talks provide a great opportunity to interview Ethan Daniels, a trained marine biologist and a truly gifted photographer.”

Mystery bone revealed!/?

Human pelvis and sacrum. The acetabulum is the site of the hip joint, where the femur attaches.

Well, here is what I can provide by way of explanation for the mysterious bone Anne Hess found in Maine. The things I know for sure: this is a bone from the sacral (base of the spine) area. The sacrum in mammals is composed of variable numbers of vertebrae that fuse together during development to form a solid base of attachment for the pelvis on either side. To orient you, I have provided an image of a human sacrum with the pelvic bones still attached. You can see that the human sacrum has four holes on each side. These are the remnants of the spaces between the individual vertebrae when they fused together. The human sacrum is about 4 inches in length, and is about as wide. Most mammals have a much narrower sacrum. The reason for this is the habit exhibited by most humans of walking upright. A wide, almost triangular sacrum is needed to withstand the downward forces of an erect spine.

The specimen Anne found is only half a sacrum (it was split lengthwise), and it is a distinct relief to your blogger that this half sacrum appears far too narrow to be human. But in terms of size, at about four inches long, this sacrum must once have belonged to a rather large animal. So, what’s my guess? I would venture to say that this may be a deer sacrum. The size would be about right, and the shape resembles that of both bison and reindeer sacra (yep, busting out the Latin plurals, ladies and gentlemen) that I found on the all-knowing internet. Here’s a fantastic side by side of a human versus a deer sacrum:

Northern Fulmar spine and pelvis--note the extensive fusing of vertebrae and also the very small overall size.

Finally, because I cannot write a post that is entirely devoid of seabirds, here is a bit of comparative anatomy for you. How can we tell that this half sacrum found by Anne is mammalian at all, and not avian? Take a look at this photo of a Northern Fulmar spine and pelvis. Birds exhibit a general evolutionary theme of fusing bones together in the pursuit of both weight economy, and a rigid skeleton that can withstand the forces of flight. To that end, birds have not only a few fused vertebrae forming a sacrum, but a structure known as the synsacrum, which incorporates a whopping fourteen fused vertebrae, and in some species, is also fused to part of the pelvis. At the top of the photo of the fulmar skeleton, you can see what appears to be a smooth, continuous ridge of bone. This continuous ridge actually represents several fused vertebrae.

Beyond the substantial anatomical differences, note also the massive size difference here. While Anne’s specimen was about 4 inches long, a similar segment of fulmar synsacrum would be only about 3/4″ long. And a fulmar is no wispy little songbird either. Thus, Anne’s find, were it possible that it were avian, would apparently have belonged to an enormous prehistoric emu.

Thanks to Anne for providing the fodder for this little exercise. I certainly enjoyed my research on the subject, though it has now consumed an absurd part of what might have been a productive morning. Nonetheless, please do send in any and all photos of mysterious dead things, Seanetters!