Tuesday, May 29, 2012

Warblings in Wake!

Emails were flying around over the long weekend about a pair of Warbler Vireos nesting in Raleigh.  I really wanted to see these birds, but was stuck up in New England (looking at different Warbling Vireos, among other birds).  So as soon as I got home and had the chance, I zipped out to Shelley Lake Park to see them for myself.

Why are these birds so special?  Well, just take a look a Cornell's breeding range map for the species...

(map by Cornell Lab of Ornithology)

Central North Carolina is just about the only spot in the country that these birds should not be breeding.  Yet here one is nesting in Wake County....

Female Warbling Vireo nesting in Raleigh
And this is a species that is tricky to find anywhere in NC (state bird #313 for me!).

I've heard birders say that song birds don't sing when they're sitting on eggs.

Male Warbling Vireo singing while incubating

Well it wasn't true with this pair at least.  I saw the female fly off the nest and then off to forage and the male take her place and continue singing away while incubating the eggs (a rare male multi-tasker!).  And when he wasn't on the nest he was very busy chasing away grackles.

It will be interesting to see how this pair does so far out of their expect range and in a spot with such a high density of nest predators (i.e. grackles, crows, Blue Jays). The odds-makers on the carolinabirds listeserve don't seem to have much confidence!

Congratulation to Lynn Erla Beagle and her group from Wake Audubon for finding this unusual pair.  And thanks to Mike Turner for posting detailed instructions and GPS coordinates that many folks (including me) used to easily locate the nest. 

Thursday, May 24, 2012

Searching for Ceruleans on the Roanoke

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.  

The team -- photo by Ken Hackney

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.

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.
Bald Eagle
And Prothonotary Warbler was among the most abundant species of the day.  
Prothonotary Warbler
 This Prothonotary nestling enjoys a spectacular view of the Roanoke from its dead tree trunk penthouse (penthole?). 
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.
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…
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.

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.   

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.

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!

Tuesday, May 15, 2012

locally grown Yellow-crowned Night-Herons

Over the weekend I investigated the suspicious rumors of Yellow-crowned Night-Herons nesting in marshes around Durham and Chapel Hill.  What could these birds possibly be doing around the triangle, when they should be down at the beach?  Eating crayfish and raising young?  Likely story!

And by "rumors" I just mean great photos of nests taken by top local birders...clearly this was a mystery in need of investigation!

Luckily I was able to convince Will Cook to let me cover the highway 54 waterfowl impoundments for the Chapel Hill Spring Bird count.  I had never birded these spots before (until recently I thought they were duck prisons and I'm not into captive birds), so I wasn't sure what to expect.

But when I arrived at dawn, lo and behold the trees were filled with Yellow-crowned Night-Herons!
Yellow-crowned Night-Herons at the New Hope Creek waterfowl impoundment
Well, actually I only counted 7, but it was still a heck of a lot more Night-Heron action than I expected to find!

When I passed back by their haunt at 9 am, there wasn't a single one left to be found.  They had all gone off to roost for the day I assume.  They are Night-Herons after all, so-called because of their nocturnal (or maybe crepuscular?) behavior.

Look at those toes! How can that be comfortable?

I'm not sure whether the local population is growing or it's just that birders aren't at these little artificial highway-side marshes at dawn very often (I suspect both).  All I know is that there is a ton of habitat similar to the area I covered that is either inaccessible or virtually never checked.

A simple extrapolation leads me to believe that at least several dozen Yellow-crowned Night-Herons must breed in the area.  Yet until 5 or 6 years ago these birds were almost never detected on area spring bird counts.  The previous record high count for the Chapel Hill Spring Count was 11 individuals.  If only I could have been at two impoundments at once perhaps I could have broken the record...

Oh well, maybe next year!

Monday, May 7, 2012

Spring Sprang Sprung

It has been a whirlwind the past few weeks with birding, term papers and field work…and now I find myself finally updating this blog with the first week of May gone.  Most of the exciting spring migrants have already passed over the rapidly warming central piedmont in favor of higher latitudes and elevations. 

Blackpoll Warbler

I saw this Blackpoll Warbler out my window the other day; a harbinger of the beginning of the end of spring migration.

According to the old-timers at the Carolina Club’s 75th Anniversary meeting in Raleigh this past weekend, the rain storms just didn’t come at the right time to cause the fallout that every birder prays for in spring.  As a result many of the uncommon transient warblers were downright rare.  Nevertheless through two full days of leading area field trips for CBC participants I was able to turn up 21 warbler species.  Not bad at all!

Of course this says more about the sites I was assigned than anything else.  

On my Saturday morning trip to the ever popular birding hotspot, Mason Farm, we stumbled upon one migrant flock that had a Magnolia and Cape May Warbler—both gorgeous males!  And the entry marsh had a about a dozen sandpipers: mostly Solitary with a few Least and a Spotted. 

In the afternoon I took a smaller group to Eno River State Park where we got Rose-breasted Grosbeaks, Scarlet Tanagers and lots of Black-throated Blue Warblers.  But the coolest sighting might have been the Red-shouldered Hawk that flew by with a snake in its bill.  
My co-leader, Mike McCloy, showing CBC members a Kentucky Warbler at Howell Woods

On Friday I led a group to Howell Woods down in Johnston County, which is thick with bottomland swamp species such as Hooded Warbler, Kentucky Warbler and Acadian Flycatcher. 

Acadian Flycatcher
It even has the elusive Swainson’s Warbler, which cooperatively sat up and sang for the group giving nearly everyone fantastic looks and me a passable photo of lifer #1553!

Swainson's Warbler!
Legendary naturalist Scott Weidensaul was in our group and even he was thrilled by this bird.  Or at least he said as much before electrifying the club and visitors with a talk about the wonders of bird migration.  Both Scott’s presentation and the venue, the recently completed North Carolina Museum of Natural Sciences, left me awestruck.  It was a fantastic way to cap the meeting.  


Last weekend I covered Quail Roost with Tom Krakauer for the Durham spring bird count again and we crushed our total from last year by about 10 species.  We had Natalia Ocampo-Penuela partially to thank for this; she came along to get a few life birds and ended up spotting one of the better birds of the count: a gorgeous male Blackburnian Warbler!  But the best bird for me was a flock of about 120 Bobolinks we found in a field of alfalfa. 
Bobolinks! Durham bird #204

Since the count was in late April, it was the first chance to see many of the returning breeding birds singing away on territory, such as this Blue Grosbeak…
Blue Grosbeak

…or this Yellow-breasted Chat.
Yellow-breasted Chat

We also saw a nice male Orchard Oriole.  
Orchard Oriole
There’s still time for some late-moving migrants, but once June rolls around and the summer heat really fires up I recommend visiting the beach or the coast...and to bring a bathing suit as well as binoculars!