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)

Dead Bird Quiz: Mainers only edition

25 11 2014

In advance of the Thanksgiving holiday, I thought you would all probably be longing for a DBQ. So here are two birds found by Mainers in October:

Bird A:

Bird A (photo: B&C Grunden)

Bird A (photo: B&C Grunden)

Bird B:

Bird B (Photo: S & R Brezinski)

Bird B (Photo: S & R Brezinski)

Neither of them are turkeys, by way of a hint.

News flash: citizen scientists are trainable

20 11 2014

Not to be smug about it, but SEANET has been doing citizen science since before citizen science was cool. Or at least, since before it was widely accepted as a viable and valid method of collecting large scale data sets. For a long time, the critique from the science establishment was that lay people without formal science training could not match the quality of data generated by trained scientists. Over time, more and more citizen science projects have taken off and produced high quality data sets on a scale impossible for scientists and their exhausted grad student minions to replicate. Now, in the face of these data, many former naysayers have had to admit that citizen science plays a role nothing else can. Professional scientists needn’t have feared; the rise of citizen science can, in many cases, free them up to do things besides constantly collecting data themselves. Study design, data analysis, publication of results, all these things remain in their purview.

As these views have evolved, it has remained critical to ensure that citizen scientists, who often collect data with little to no direct supervision, are actually doing a good job. In some projects, that requires intensive training before joining up–learning how to identify organisms, or take measurements with accuracy and precision, for example. These trainings were often in person and labor intensive, and sometimes also cost prohibitive, so many programs began looking for alternative methods of training, whether with print materials or mult-media ones.

The slick and flashy app interface of the Outsmart cit sci project.

The slick and flashy app interface of the Outsmart cit sci project.

A new study out in PLOS one looked into the relative effectveness of print vs. video training for volunteers monitoring invasive plant species in Massachusetts. They determined that video training out performs plain print resources (photos and text descriptions of plants), but, perhaps more importantly, rivals in person training in preparing volunteers who can correctly identify invasive species. Moreover, when volunteers did incorrectly identify species, they tended to be plants that were challenging for all volunteers, regardless of how they were trained. Identifying exotic honeysuckles, for instance, is hard for almost everyone, while multiflora rose was identified by nearly 100% of volunteers.

For SEANET, we have chosen to put more work in on the back end of data collection. Our volunteers are not required to have any knowledge of species identification when they join (though they tend to acquire it if they stick around); instead, every bird must be photographed so that it can be reviewed for accuracy as to species. For a program of SEANET’s relatively modest size, this works well, and I am able to review everyone’s reports individually. But on a scaled up project–something like ebird for instance–the program leaders must rely on the volunteer’s abilities and experience, and only reports that seem strange or outlandish are challenged and followed up on. If SEANET were to get so big as that, we’d have to modify things.

One thing the invasive plant project studied in this article has that I do indeed covet is a very slick and attractive interface in a smartphone app. We’ve talked about having such a thing for SEANET for a long time, but as of now, it’s not in the cards. But you can all gaze in wondering admiration at this plant project’s interface, and, if you are located in the northeast, you might even consider participating. If, of course, it wouldn’t cut into your Seanetting.

Carnage on the coast!

18 11 2014

The title here may be somewhat hyperbolic, but the situation on Gil Grant’s North Carolina beach on November 10 was striking. Gil found 7 dead birds, all of which had been thoroughly dismembered and stripped of flesh. For the most part, all that remained were wings and the occasional flayed skull. Six of the birds were laughing gulls, and one was a ring-billed gull.

ggrant6834-16287Whenever several specimens of a single species or closely related species turn up dead at the same time, we always have to consider a disease as a possible cause. But what else could it potentially be? Gil pointed out one likely suspect himself, writing this note on his report: “all 7 gulls today within 1/2 mile of fishing pier, gill nets, and shrimp boats.”

Nice clean skull, possibly thanks to ghost crabs.

Nice clean skull, possibly thanks to ghost crabs.

This is a situation we encounter a few times a year: a suspected case of bycatch, where birds are entangled and killed in fishing gear and then tossed aside. The diagnosis is not easy to make, however, even in fresh carcasses. When a bird is documented coming up dead in a net or other gear, the case is fairly clear. But we often get only a waterlogged carcass washing up on a beach, and it’s much harder to attribute those deaths to bycatch. The situation on Gil’s beach is further complicated by the heavy scavenging of these carcasses.

ggrant6826-16283This scenario is common–larger scavengers like other gulls pick the carcasses apart, and then, on southern beaches, it appears that ghost crabs do a thorough job of cleaning almost all the remaining flesh off the bones with remarkable speed. You can see a crab burrow near a carcass in one of these photos. We don’t see quite this much cleaning off of bones up here in the north, which, to me, is further support of my ghost crab hypothesis, since we don’t have them up here.

Because of the scavenging, there is no way to determine a definitive cause of death in these birds. But we have at least documented the presence of these several carcasses. I have been chatting with researchers interested in tracking bycatch and marine debris, and they are also interested in these more circumstantial cases, so we may soon be contributing photos from cases like Gil’s to that effort as well. You never know to what use your SEANET reports may be put in the name of conservation science!

The field guides are finished!

7 11 2014

SEGuideFrontCoverIt is with no small degree of personal pride that I officially announce the completion of the Field Guide to Beached Birds of the Southeastern United States by me, Sarah Courchesne. Of our initial print run of 720 books, 500 will go directly to our funder, the US Fish and Wildlife Service, for distribution to biologists and other folks both in that agency and with National Parks, or NOAA, or USDA or what have you. John Stanton will be deciding which lucky guys and gals get those. The remainder will be for us here at SEANET to decide. What I would like to offer is first dibs to any Seanetter who has put in at least a year of beach walks. You need not live in the southeast, but should I get inundated by requests, precedence will go to the southern contingent. For those who qualify, I will ask only that you pay for the shipping. Please contact me if you are one such SEANET veteran interested in a guide, and I will give you specifics on how to order it.

Once I have distributed those, I will offer up the remaining books as thank you gifts to anyone who makes a $30 or more donation to SEANET. Could there be a better Christmas gift, I ask you? I think not.

Thanks to everyone for their tolerance and forbearance over the course of this multi-year project, and I hope you all enjoy the finished product. Many, if not most, of the photos in the guide were submitted by you folks, so don’t be surprised to open up the book and see your own name, whether you actually walk in the southeast or not!


Get every new post delivered to your Inbox.

Join 59 other followers