It’s data crunch time!

31 12 2014

Today is the last day to get a survey done in 2014, dear Seanetters, and after that, the data analysis process may commence! For the past, oh, however many years, I have been occupied with the Field Guide. Now, I can turn my SEANET work hours toward something many of you have been eagerly awaiting: figuring out what patterns have emerged from your data in the past couple of years.

How I'm spending this New Year's Eve Day: verifying data!

How I’m spending this New Year’s Eve Day: verifying data!

To begin this process, I will be counting on you, Seanetters, to submit any walks from 2014 you may not have added to the database yet, and I will also be contacting anyone who reported a dead bird but did not upload a photo.

The data analysis will include the basics: number of birds found per kilometer of beach (“encounter rate”) in various regions; species breakdown; annual patterns in species. What I’d like to know from you, dear readership, whether you are a Seanetter or not, is what kinds of data are you interested in seeing? Is there something you’ve been curious about on your beach? Something you wondered about in your larger region? A particular sort of graph you’d like to see? A species emphasis?

I’m open to suggestion. This is a citizen science project after all, and you are all its citizens. I will be researching other beached bird survey data to try and be sure I am analyzing our data in a way that will make it easy to compare with data from, say, our friends over in Northern Europe, since we do share this ocean with them. Beyond that, I am not wedded to any particular analysis. That’s the beauty, I suppose, of my training not as a scientist, but as a veterinarian. At least, I am trying to look on the bright side of that, and ignore any deficits.

Happy New Year everyone! I am grateful for your energy, commitment, attention and interest, whether you walk for us, read the blog, or help me figure out what that odd bit of feather and gristle might be. Here’s to a great 2015!

Island bird quiz answers

19 12 2014

This is one of those quizzes that’s made me feel rather good about my abilities. While I encounter a lot of wings in my work verifying SEANET reports, we don’t get many skulls, so I am always a bit leery of trying those. My basic strategy is not particularly systematic; I look at the skull and see what jumps to mind, and then I check to either confirm or deny my suspicions. When I looked at Skull 1, I thought oystercatcher immediately. I was therefore gratified to find that American Oystercatchers (AMOY) do breed on the island where this skull was found, and also that our readers concurred; Wouter, Edward and James all asserted AMOY as well. When I considered a bit more what had made me jump to this i.d., I came up with the bill shape, which is long and has a long nasal aperture (the opening on the upper bill). The shape of the cranium is very rounded, with a open, round orbit (eye socket). It reminded me somewhat of a woodcock, which makes sense since the two species are shorebirds by classification. Though the woodcock stalks the woodlands eating worms and such, their skull anatomy reveals their affiliation. The finder of this skull was also curious whether we could tell the age of the AMOY based on the skull. I don’t know, but if anyone would, it’s our esteemed readership, so if they have thoughts on that, I hope they will weigh in. But in any case, check out these dome-headed cousins!

Eurasian woodcock (photo: Ronald Slabke)

Eurasian woodcock (photo: Ronald Slabke)

American Oystercatcher (Photo: Peter Wallack)

American Oystercatcher (Photo: Peter Wallack)

The second skull is a more familiar friend. The bill is clearly a gull’s, though it can be challenging to tell a Great Black-backed from a Herring Gull, especially with only an oblique view and no measurements. I tend to be conservative on these i.d.s, at least for the purposes of our database, so I would not likely go further than to say it’s a large gull–either GBBG or HERG.

The set of wings at first looked like a tough call. The overall roundish shape and dark color got me thinking of a duck, but a nondescript dark wing could be a lot of kinds of ducks. On close inspection though, I was gratified to see a little hint of bluish purple on a couple of the feathers that I suspect are the remnants of a speculum. What birds have a bluish speculum? Mallards and American Black Ducks do. How can we tell the difference? In this case, it’s challenging. These wings are pretty far gone. The two best ways to differentiate the wings are by the presence (Mallard) or absence (ABDU) of white bars bordering the speculum, and, on the underside of the wing, a characteristic brown streaking at the wrist in ABDU, and plain white in Mallards. That region of the underwing is thoroughly degraded in our mystery bird, and I am leery of judging too much based on what’s left of the upper wing, but I don’t see much evidence of any white borders anywhere here. I would, therefore, lean toward ABDU in this case. Though I am open to discussion and correction, as ever, dear readers.

This American Black Duck is trying to show you both the upper and underwing characteristics of his species. (Photo: Dick Daniels)

This American Black Duck is trying to show you both the upper and underwing characteristics of his species. (Photo: Dick Daniels)

And look at this obliging Mallard's wing. (Photo: Malene Thyssen)

And look at this obliging Mallard’s wing. (Photo: Malene Thyssen)

Island views, New England style

17 12 2014

Usually, I manage to juggle my SEANET responsibilities amid my teaching ones. These past couple of weeks, as I descended into finals and student hysteria, I had to entirely toggle off you all and this blog. Apologies for that, but I submitted final grades today, and now turn my attention to you all once again. Today, I have a request for help with identifications on some mystery skulls and weathered wings–it seems our reputation precedes us on that score.

The photos come from an island off the Massachusetts coast, and as I paged through them all, there was a good bit of evidence of muskrat activity–trails, little piles of vegetation, and scat everywhere. Muskrats are native to New England, but when they manage to get out to distant islands, and their predators don’t follow, artificially high numbers can result.

Appledore Island in Maine has historically had a high muskrat population as well, and the animals have become so acclimated to humans that they scamper around in plain sight and approach people unnervingly closely. Last summer, however, there was a conspicuous lack of these rodentine islanders. It seems likely that the Snowy Owls that overwintered on the Isles of Shoals fed heavily on the muskrats, to the extent that I did not see a single one during my week on the island. Their homes and trails looked fairly deserted, and muskrat bones and leathery, weathered skin lay strewn about on all the trails.

There were owls up and down the New England coast this past winter, so it may be that the muskrat populations are reduced on other islands too. But on all these islands, unless every last muskrat was eaten, their populations will likely rebound now that the predation pressure is back down to low levels.

Now, for your perusal, the dead bird photos.  I have my strong suspicions regarding their identities, but I want to get some unbiased opinions from you all first.


Mystery skull 1.


Mystery Skull 2.

Mystery wings.

Mystery wings.

DBQ answers

2 12 2014
Bird A as it might have looked in life. (Photo: Wikimedia Commons)

Bird A as it might have looked in life. (Photo: Wikimedia Commons)

I could well have termed this quiz “The yellow on the mandible edition” as that feature is telling in both these birds. All my respondents identified Bird A as a Yellow-billed Cuckoo, and I included that one not because it was tricky overall, but mainly because it’s an oddity. It’s not that this species is so rare, but its occurrence on a Maine beach might be considered notable for two reasons: Maine wildlife authorities report that the bird does occur in the south and central regions of the state, but is quite uncommon in the northern part of the state. We, then, are seeing this bird roughly at the northern limit of its range. Already less common in Maine than its cousin, the Black-billed Cuckoo, population estimates on the Yellow-billed Cuckoo show it declining, likely due mainly to habitat fragmentation (the birds prefer dense undergrowth for foraging). Maine lists the YB Cuckoo on its list of of species of special concern, and in the western and southwestern regions of the U.S., the species has been in precipitous decline, with some discussion of endangered status.

A deceived reed warbler attempts to keep fed a gigantic European Cuckoo chick in its nest. (Photo: Per Harald Olsen)

A deceived Reed Warbler attempts to keep fed a gigantic European Cuckoo chick in its nest. (Photo: Per Harald Olsen)

Interestingly, the Yellow-billed Cuckoo occasionally lays its eggs in the nest of another bird, engaging in what is known as brood parasitism, but very often builds its own nest and rears its own young. This is in contrast with the European Cuckoo, which is, as I understand it, an obligate brood parasite, much like our Brown Cowbird. It was the European Cuckoo whose actions drew the moral disapproval of medieval Europeans, giving us the term “cuckold.” It seems the Yellow-billed Cuckoo is slightly more virtuous, by those lights.


As to Bird B, I had hoped this one might generate a bit more discussion, and it appears that it did. All our respondents (Edward, James, Mary, and Maureen) placed this bird in the pouch bill group, which includes pelicans, gannets, cormorants, and frigatebirds, among others. These birds are distinguished by their variable throat pouch, and, in most cases, by the distinctive webbing involving all four toes. Maureen suggested Magnificent Frigatebird, though it would be pretty far north for that species, but to be sure, we do occasionally see them turn up. In fact, one of the photos of that species in our new field guide is of a bird that turned up dead on Sable Island in Canada! More importantly than geography in this case, however, is anatomy. While most pouchbills have strongly webbed, fleshy feet, frigatebirds have rather spindly toes with scarcely any webbing. This reflects their natural history as birds that do not land on the water or swim and dive as their cormorant and gannet brethren. Instead, they snatch food from the water’s surface while on the wing, or shakes down other birds for their catch, a behavior known as kleptoparasitism.

Another species of Frigatebird, but with the typical Frigatebird feet (Photo: Aviceda)

Another species of Frigatebird, but with the typical Frigatebird feet (Photo: Aviceda)

So the feet on our Bird B alone point us away from Frigatebird, as does the bill, which would be longer and more slender in a Frigatebird. The rest of our respondents identified Bird B as a cormorant, but were split as to species. We’ve been through this before, trying to distinguish Great Cormorant from Double-crested, which can be a challenging i.d. depending on the state of the carcass. I included this case because of the white appearance of the head in Bird B. Generally, a conspicuous white patch at the bill base is characteristic of Great Cormorants. Bird B shows white over much of the face, which led me to suspect that the color was an artifact of decomposition. We do see feather and skin sloughing, especially in water-logged carcasses, which this bird appears to be, so the white color on the head of this bird was not present in life. The feather sloughing is also clearly visible over the wings. We are left without the color of the skin at the base of the bill to go on, which often clinches the i.d. in this case. What we do have is the color of the mandible itself, which has a yellowish tinge in Bird B. When we look at the two candidate cormorant species, only the Double-crested shows that, and it is strongly present in juveniles, fading to gray in adults. Thus, I am with Edward on this one, identifying it as a juvenile Double-crested Cormorant.

Double-crested Cormorant showing yellowish mandible. (Photo: Hans Stieglitz)

Double-crested Cormorant showing yellowish mandible. (Photo: Hans Stieglitz)