The Cerulean Warbler is a special bird. Not only is it the only member of the huge wood-warbler family that is entirely blue and white, but it also has the tragic distinction of
being one of the most rapidly declining neotropical migrant songbirds. On average
the population shrinks 3 percent each year and has been doing so for decades. It isn’t entirely understood why the species
is struggling so, but the downhill trajectory combined with a low population
density has earned it a spot on the IUCN’s endangered species list where it carries the label, “Vulnerable.”
Because Ceruleans nest in emergent trees in mature forest,
they are nearly impossible to spot without first being heard. To get at this bird typically
requires a special trip to a special known breeding location during the late spring when the males proclaim their presence with a buzzy song that
sputters like a tiny gas motor trying to start.
Since ~99.9% of Cerlueans breed in the mountains, that’s where nearly
everyone goes to add this special bird to a life, state or year list.
What we set out to do was find that remnant 0.1% of the
population that somehow persists miles from all its relatives in a completely
different physiographic region
in riparian forest along the Roanoke River in the coastal plain of North
Carolina.
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| The
team -- photo by Ken Hackney
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Paul
Taillie, Natalia Ocampo-Penuela, Mark Kosiewski, Nick Flanders, and I paddling a 15-mile stretch of river going downstream from Weldon,
listening intently, hoping to pick out that Cerulean song.
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| Birding by kayak |
We had perfect weather—clear skies and highs around 75—and perfect
timing. We were late enough to avoid
fishing boats (we saw two all day) and early enough to beat the mosquitos (my
count was one individual for the weekend).
And the river was flowing nicely, so that in the early hours of the
morning when the birding was best, we scarcely had to paddle, but would just drift and listen.
And the river was gorgeous and fantastic for birds. At any given time two or more Bald Eagles
were typically in view.
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| Bald Eagle |
And Prothonotary Warbler was among the most abundant species
of the day.
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| Prothonotary Warbler
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This Prothonotary nestling enjoys a spectacular view of the Roanoke from
its dead tree trunk penthouse (penthole?).
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| Prothonotary Nestling |
We found 15 warbler species on the day. It was a little late for migrants and we
detected only two: Blackpoll and Yellow, but we recorded 10 singing males of
each of two rather secretive and rare breeders, Swainson’s and Kentucky, and
got great looks at both.
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| Kentucky Warbler |
And yes, we found our Cerulean Warblers…six males singing
away, perhaps hoping to lure in a female from what must be a severely limited
supply. We beached our boats and
clambered up the steep bank to try to spot one…
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| !! |
We were thrilled to see our first of 3 seen Cerlueans on the
day, but what was shocking was the trashed habitat where this one had decided
to stake out its territory.
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| Prime Cerulean Warbler habitat? |
While there were some tall Tulip Poplars (a species they
tend to prefer), the forest cover was fragmented by little clear-cuts. Even
where the canopy was mostly intact there was evidence of active selective logging. We saw stumps and freshly downed tree crowns.
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| Singing |
Sadly this bird may be singing in vain. Even if he is able to successfully breed in
his fragment this year, will there be anything for him in 2013? Indeed the prospects for this tiny population
are grim (even more so than they are for the species as a whole).
Were the Roanoke Ceruleans, with their isolation, given
thousands of years to breed and respond to selective pressures, they might
genetically drift to a novel subspecific identity. But I’m not sure if this population will make it through the
current century.
One of North Carolina’s preeminent birders and naturalists,
Harry LeGrand, recently reported zero Ceruleans in at least 12-15 trips to
the Roanoke this spring (all working on foot, essentially just in Halifax
and Northampton). He concluded that Ceruleans are "...in considerable decline here."
The good news is that there are large swaths of Roanoke riparian
corridor that are protected (i.e. by the nature Conservancy), though I’m not
sure how well they correspond with these Ceruleans’ Alamo just south of
Weldon. And the problem may very well be with wintering habitat, or something unrelated to the state of the forest buffer along the Roanoke.
Of course, we were having far too much fun to worry
too much about
the birds’ fate. With the stream flowing
well we made it to the Tillery camping platform (reserved through
Roanoke RiverPartners) before 3pm, leaving plenty of time to relax, have a swim, and fish.
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| Camping on the Roanoke |
And it was a spectacular flawless weekend. We ended up with 90 or so species as a group. Other highlinghts included one Scarlet Tanager, a singing Horned Lark, a singing Grasshopper Sparrow, Loggerhead Shrikes, a Yellow-crowned Night-Heron, and a stop by Sylvan Heights Waterfowl Park to see the menagerie before heading back to the Triangle on Sunday.
So I would highly recommend having a paddle on the Roanoke. And if you hope to find Cerulean Warblers away from the mountains, I would recommend planning your trip soon!
