Reflections on the century

Friends, there it is, the 100th species on my Somerville list:  the swamp sparrow. When I last wrote about the state of the species list, in February of this year, I had 71 species on the list.  At that time, I reckoned it would take me another six years to reach my goal of 100.  Instead, it took me not much longer than six months.  (And in fact, since I got to 100 with my dear friend the swamp sparrow, I've actually gotten three species more -- belted kingfisher, pied-billed grebe, and Cooper's hawk, plus eastern wood-peewee, misclassified earlier.)

So what to think about this?  Does it turn out that Somerville is actually a birder's paradise?  Even though, according to the Charles River Watershed Association, fully 77% of Somerville is paved over?

Well, the satellite doesn't lie.  There is precious little green in Somerville (and ironically enough, the largest green patch on this map has since been paved).  Here's a data point to consider:  at Mt. Auburn Cemetery (visible a bit below Fresh Pond on the lower left), there have been 218 species recorded, according to eBird.  It's nice and green there.  But it also has to be said that people -- and competent people at that -- have been looking much harder and longer in Mt. Auburn than they have in Somerville.  So forgive me if I think that 100 (or 104, really) isn't too disgraceful, given the material I have to work with.

In other words, while Somerville might look entirely hopeless from a birding perspective, it actually isn't. Its saving graces number no more than two, but they're important.

The first is the Mystic.  Degraded as this river is, and though mostly man-made in its current form, it still offers aquatic life, animal and vegetable, on which a certain number of birds depend.  And, because in Somerville the Mystic has both a freshwater and a saltwater piece, it serves two different bird populations, both of which have a large migratory component.  So as birds move south, or range up and down the coast in winter, the Mystic offers a sheltered stopover where they can rest and feed.  Further, the fringe of vegetation on the river bank, though rarely more than ten yards wide, gives shelter to a surprisingly large range of birds -- particularly various species of native sparrows.

The second saving grace is the migrant-trap effect.  Because Somerville, and the adjoining towns, are so paved, the few spots of green tend to concentrate migrants as they pass over.  This phenomenon is the secret to why Mt. Auburn sees so many species; but it's true for us as well, though to a much smaller extent. Prospect Hill, both the park and people's yards adjoining it, is the salient example of this phenomenon in Somerville.  The bike path, to a limited extent, has the same function, as does Alewife Brook.

Now, don't think I'm talking up Somerville as a birding destination.  It just isn't, particularly since within five miles of Somerville there are a number of vastly more plausible and rewarding birding destinations.  But for those of us who live here, there's something to be said for appreciating what we've got.

And what we've got, at the current hour, is 104 species.

The rowan stripped bare by her thrushes even

Around here, we see winter in and out the same way -- with thrushes.  Swainson's thrush, seen here, is not one of our usual clients.  Discounting the robins, the thrushes we see in bulk are hermit thrushes, and they tend to arrive earlier, and leave later, than other migrants.  By the time they get here -- October, mostly --  there will be no berries left on the mountain ash; the robins will have eaten them all.  This Swainson's was sharp enough to arrive before the buffet closed.  The hermit thrushes will have to eat something else.

I've seen a few other odd migrants pass through -- a redstart, a phoebe.  Keep your glasses nigh... there'll be more.

Somerville beach

It is a fact not widely appreciated, but Somerville has a bit of seacoast.  From the Amelia Earhart Dam to the T maintenance yard, a hundred-odd yards, the water is more sea than river.  How do we know?  Because the water tastes of salt, and the creatures in it are brinier than they are upstream.  Here, for example, is a Somerville hermit crab (sporting a Somerville barnacle), captured just under the railway bridge:

And so, as a coastal town, however nominally, we have a right to a certain number of shorebirds, such as the least sandpiper shown above.  But as it happens, the shorebirds are much more attracted to the mats of water chestnuts in the fresh water upstream -- a feature the authorities abhor to such an extent that they have employed mechanized harvesters to uproot it.

Recent weeks have seen significant numbers of waders there, not just the least sandpipers, but spotted sandpipers...

and lesser yellowlegs:

Waxwings and water chestnuts

The water chestnut is an invasive species hereabouts, choking ponds and waterways like the Mystic.  It's expensive and laborious to remove, and always comes back.  But the cedar waxwings, bless their hearts, love the stuff.  It makes huge rafts, rigid enough to land on, and contains something that they go crazy for.  I have no idea what it is, whether animal or vegetable.  This last week (and maybe longer, for all I know), waxwings have been present in big numbers on the Mystic -- more than I've ever seen in one place. A hundred at least.

And speaking of the Mystic, the path that runs from the dam up to the boathouse continues to get a makeover. They've somewhat unwisely planted much of it in grass.  I guess they just love the Canada geese that much. Anyway, the other day they had the sprinklers going, and one sprinkler head drew an unusual assemblage of birds:

That's a starling at top, a robin at left, and in the middle, red-winged blackbird and a yellow warbler.  There was in fact a pair of these warblers there, which is interesting, because it says to me they're probably nesting in the vicinity -- and if so, that's the first pair of warblers I've ever known to nest in Somerville.

Carolina wren, plus a fish

Most birds I encounter here can be categorized in one of two ways:  either they live here, or they visit on a more or less predictable schedule.  The Carolina wren is one of the exceptions.  They appear and disappear erratically, mostly in summer and fall, and never in winter, though they're supposedly a year-round resident of these climes.  As to habitat, my Aubudon bird app claims "woodland thickets, ravines, and rocky slopes covered with brush."  Isn't that just Somerville in a nutshell.

Surprisingly, they're the most common wren I see.  I've seen other wrens sporadically, but it's a bit mystifying that house wrens aren't common nesters here.  After all, while we're short of woodland thickets and ravines, we do have quite a few houses.

But enough about wrens.  Here's a chickadee pretending to be a fish:

Warbler wrapup, 2013

It's now pushing July, and the warblers have been gone for nearly a month, but I've been so busy I haven't had a chance to tabulate them.

But here, finally, is what I've got -- 13 species, as follows, with the number of each sighted:

• American redstart, 2
• Black-and-white, 6
• Blackpoll, 2
• Black-throated blue, 2
• Cape May, 2
• Common yellowthroat, 12
• Magnolia, 8
• Nashville, 3
• Northern parula, 4
• Ovenbird, 3
• Palm, 1
• Yellow, 9
• Yellow-rumped, 9

All of these species are depicted in the photo mosaic above, kindly put together by my father.  (And just to fill out the grid, there are a couple of warblers in there I wasn't able to identify as to species.)  All were seen between the fifth and 30th of May, with sightings every day until the last week, where there was a gap of several days.  The common yellowthroat was our winner this year, with sightings on 12 different days.  While sightings were fairly well distributed throughout the month, May 10th represented a definite high point.  That day brought in not only a wave of different warbler species, but the catbirds and chimney swifts as well.

I expanded my field of search beyond Prospect Hill this year, to take in the Mystic, and on one occasion, Alewife Brook.  Maybe there are other areas in Somerville warblers are to be seen (the bike path, for example), but I think the Mystic and Prospect Hill are the best bets.

I take it to be the case that the fact of a warbler species appearing in Somerville testifies to the strength of that warbler's numbers in Massachusetts as a whole.  To put it another way, we don't get too many rarities here.  This year I did see two species I had never logged before (Nashville and Cape May), but the others are ones I see every year -- not exactly like clockwork, but reliably enough.

But the chief thing is that these are all migrants.  So far as I can tell, no warbler species breeds here in Somerville.  We're merely a corridor for them, a temporary place of rest.  In spring, they appear in some strength, in the fall, much less so.  Now it's summer, and things have gone quiet again.

A confusion of flycatchers

It's now almost June, and as the wheels of the migration turn, we get flycatchers. Now, flycatchers are famously hard to identify as to species, and the four (or is it three?) pictured above, all of whom showed up in my neighbor's yard today, are all confounding me in one way or another.  Start with the one on the left: what's your pleasure, willow or alder?  It didn't make a sound, so who knows?  But is it the same bird as flycatcher number four?  It could well be; the pictures were taken hours apart.

On to flycatcher number two.  I call it yellow-bellied, on the grounds that it is, sort of, but then why is its throat so white? Is that okay?  And it's the same problem with flycatcher number three.  I think it's a great crested flycatcher, but again, it's not very yellow down there, is it?

Meanwhile, I'm trying to put together an account of the warblers that went through in May.  There were still a few showing up today, so I'm entitled to a few days' grace period.  It's going to take me forever to deal with the photos anyway.

POSTSCRIPT:  Looking back at these pictures, at some months' remove, I'm now convinced that picture number one is of an eastern wood-pewee, and not an Empidonax flycatcher at all.  Meanwhile, number two does seem to be the yellow-bellied flycatcher, and number three the great crested.  I still can't make up my mind about picture number four.