Monday, May 28, 2012

Photo Study of Semipalmated Sandpipers at Kimble's Beach, NJ

By Luke Musher
As you may know we've been banding lots of Semipalmated Sandpipers, so naturally I've had a lot of opportunities to photograph them.  Here are some recent photos I took at Kimble's Beach in Cape May county, while banding some Semis caught in cannon nets by the international shorebird team earlier this week.
With a Ruddy Turnstone.
Eating tasty horseshoe crab eggs

The word semipalmated means partially webbed.  Here you can see the webbing in between their toes.

Saturday, May 26, 2012

Banded Shorebirds on Delaware Bay

By Luke Musher

Since the mid 1990's biologists have been banding shorebirds along the Delaware Bay shore, a body of water that is an incredibly important stopover site for hundreds of thousands of shorebirds including Red Knot, Ruddy Turnstone, Sanderling, Semipalmated Sandpiper, and many other species.  The main reason that the bay is so critical is the coincidence of shorebird migration and the spawning of horseshoe crabs. Many shorebirds double their weight during their time spent at Delaware Bay, building important fat stores for migration by consuming the crab eggs that become exposed on the beaches, river mouths, and even marshes.
Part of the 1%.  A Semipalmated Sandpiper banded along the Delaware Bay shore in 2010  or earlier that  we recaptured last week.
One method that biologists are using, including the team I work on studying Semipalmated Sandpipers (hereafter SESA), is putting colored flags with unique codes on the birds.  These birds can then be re-sighted by birders.  The recapture rate of these banded shorebirds is roughly 1%, but by flagging the birds biologists can get a 10% return.  Thousands of Red Knots, SESA, Sanderling, and Ruddy Turnstone have been flagged both on Delaware Bay, and on their wintering grounds in South America, and each location has its own flag color.  For example, while woosh-netting at Fortescue this week, we re-sighted a Red Knot with an orange flag.  Although we could not get a combination from it, we knew it had been banded in Argentina by the color of the flag.
One of a few hundred Red Knot present at Fortescue last week, and one of only a few that was flagged.  [Photo by Luke Musher]
Biologists have long pointed out that the shorebirds are feeding almost exclusively on the horseshoe crab eggs while they are here, but certainly many thousands of birds feed elsewhere, away from exposed eggs such as on mudflats in the back bays and marshes at low tide.  The work I am doing with NJ Audubon is continuing what has been done along Delaware Bay for the past two and a half decades, but also supplementing those data with information on what these birds, specifically SESA, are eating.

By taking blood from the shorebirds, we can not only use genetics to find out the sex of each individual we capture, but also fairly accurately evaluate the diet of these shorebirds as they stopover along the bay.  For example, horseshoe crab eggs and marine invertebrates that shorebirds feed on in mudflats have different isotopic signals.  I wont go into too many details about how stable isotopes work or what they even are (this will most certainly bore you and me and probably stable isotope chemists as well), but I will tell you some basics.

Essentially, you are what you eat.  Organisms are made up of, molecularly speaking, the organisms they consume.  If a SESA eats strictly horseshoe crab eggs for days, its blood plasma will contain fatty acids that match the proportion of stable isotopes that are found in the eggs.  This is important because biologists want to know what will happen if horseshoe crab populations continue to plummet.  Will shorebirds be able to replace a diet of mainly crab eggs with other food sources?
A Semipalmated Sandpiper on Kimble's Beach, NJ just after I bled it.
Needless to say, it is very stressful for shorebirds to be netted, handled, and bled.  They already have a long, highly energy-demanding journey to complete without being consumed by predators such as Peregrine Falcons or Merlins.  They only have a short period of time to build the fat stores they need to get to the arctic, and even begin breeding (early arriving individuals may precede the availability of invertebrate prey in the arctic).  However, the more we can learn about how shorebirds utilize migrations stopover sites and wintering grounds, the more we can help to manage their populations and maximize conservation efforts.

One of the greatest parts of this project is that you, aka birders, can help too!  Many people see flagged or banded birds and report them to the USGS or biologists working in Delaware bay, and are helping tremendously with shorebird conservation efforts. Still, many people see flagged birds and never report them.  Perhaps they don't know how to do so, or don't think it matters.  If you see a flagged bird along the east coast (or anywhere for that matter), try to write down the code and flag color.  It is now incredibly easy to report flagged birds.  Delaware Bay shorebird biologists created a website,  Go on and check it out.  There's lots of great information on the project, the birds, and how to report the flags you see.  So if you're going out this month, or ever, looking at shorebirds, don't forget to look at the legs of the birds as well as plumage and structure, and write down your sightings.  Good birding1

Thursday, May 24, 2012

Up Close and Personal: Broad-winged Hawk

By Cory Ritter

It seems that Broad-winged Hawks are often seen in distant kettles, and are just specks to the naked-eye. Well, that isn't the case when you're trapping them. There are some private trappers (not affiliated with WPBO) around here at Whitefish Point, and they're kind enough to bring raptors up to the platform every now and then. The broadwings really started kicking into gear just earlier this month up here in the U.P., and on one of those days, one of the trappers, Bill, was lucky enough to catch two broadwings in his set at once--and nice enough to bring them up for me to take a look.
adult Broad-winged Hawk, in the hand, Paradise, MI
adult Broad-winged Hawk, in the hand, Paradise, MI
banded tail of an adult Broad-winged Hawk, Paradise, MI
adult Broad-winged Hawk, in the hand, Paradise, MI
adult Broad-winged Hawk, in the hand, Paradise, MI
adult Broad-winged Hawks, in the hands, Paradise, MI

Tuesday, May 22, 2012

A Texas Detour

By Cory Ritter

The next stop on my trip from California to Michigan was in Austin, TX. I went to visit my good friends Steph and Bailey, and I looked around for some birds while I was there. I didn't have anything in mind before I arrived; I just figured I'd check what had been recently sighted when I got there. I quickly formed a list of recently sighted birds I wanted to try to check out: White-tailed Hawk, Green Kingfisher, Golden-fronted Woodpecker, Black-crested Titmouse, Greater Roadrunner, Crested Caracara, Northern Bobwhite, and Pyrrhuloxia rounded out my list.

My first stop on my rounds was at Commons Ford Ranch Metropolitan Park. Golden-fronted Woodpecker, Northern Bobwhite and Greater Roadrunner had all been seen within days from when I arrived, but I struck out on all three. I did, however, encounter my lifer Ladder-backed Woodpecker, along with my year Red-bellied Woodpecker, Carolina Chickadee, and Carolina Wren. Also, I ran into what I originally thought was a Black-crested Titmouse, but it appears it may actually be a Black-crested x Tufted Titmouse.
Ladder-backed Woodpecker, Commons Ford Ranch Metropolitan Park, Austin, TX
Black-crested [x Tufted] Titmouse, Commons Ford Ranch Metropolitan Park, Austin, TX

Next I headed east to the outer limits of Austin. I went to check two spots; a small town called Utley for a recently reported White-tailed Hawk, and nearby Webberville Park for Green Kingfisher, Pyrrhuloxia, and Crested Caracara. My first stop, in Utley, was unproductive. I was going off an eBird report, and didn't have any solid information on where to find this bird, so I wasn't too surprised when my search came up empty. Either way, Webberville Park was just down the road, and I had some more birds to look for.

When I arrived at Webberville Park, I was really excited about the reported Green Kingfisher, so I started hiking along the river and there it was......nope, a Belted Kingfisher. There were plenty of Northern Cardinals, Ruby-crowned Kinglets, and American Robins. But, again, I struck out on my target birds. But, on my way out of the park I was treated to a close Greater Roadrunner. It wasn't until later that I realized I had a big thumb print on my lens, so the photo could have been better.
Greater Roadrunner, Webberville Park, Travis County, TX
I made one more stop up the road at another river access point in one last desperation attempt at the Green Kingfisher. I wasn't able to find a kingfisher, but as soon as I parked alongside the river, a Crested Caracara flew over my car! This was certainly an unexpected yet welcomed treat. Also, there was a Vesper Sparrow hopping around in the grass just a short distance from my car.

Sunday, May 20, 2012

Crabbing with Yellow-crowned Night-Herons

 Yellow-crowned Night-Herons are very much crustacean specialists, eating in large part crabs, although they will also eat small fish, frogs, reptiles and mammals just like other herons.  I've even seen them feeding in fields at night, presumably eating insects and/or mammals.  Thursday night at Heislerville I watched three, two adults and an immature bird, catch crab after crab right as the sun was setting.

Saturday, May 19, 2012

The Fortescue Feeding Frenzy

Red Knots, Dunlin, Sanderling, Semipalmated Sandpiper, Short-billed Dowitcher, Laughing Gull, etc.  See if you can pick out all these species.
Thursday and Friday this week we were woosh-netting and mist-netting at Fortescue Beach along the Delaware Bay Shore, a great spot to see the horseshoe crabs spawning and the shorebirds feeding on their fat-rich eggs.  One of the main parts of my job is taking blood from the shorebirds we catch.  The blood is then used to detect what the birds are feeding on.  Horseshoe crab eggs have a stable isotope signal that is different from that of other prey items (e.g. polychaete worms) and is detectable in the blood.  The birds at Fortescue are undoubtably feeding almost entirely on horseshoe crab eggs, and that is why we see thousands of birds there while the crabs spawn.  We had a good amount of luck there those two days, catching close to 200 birds total.  Here are some photos of the beautiful masses of shorebirds you can see there.
Red Knots, Dunlin, Sanderling, Short-billed Dowitcher, and Laughing Gull
More of the same
Dunlin and Semis (Semipalmated Sandpipers) coming in for a landing

Friday, May 18, 2012

Photo Quiz 5/14/12 Solution

Not many people responded to this quiz so I'm thinking I was asking too much of all of you to give age and plumage in addition to species.  Obviously there is not much to use here to ID this bird. Truthfully, though, the most obvious feature of this bird is the only thing you need to identify it.  That distinctive white patch on the uppertail coverts and tail base is not due to aberrant plumage, it is completely normal in all ages and plumages of this species, and this field mark is basically all you need to identify this bird.  It is a Northern Wheatear, a fairly rare bird in North America, so I'm assuming many, if not most, of you have never seen this bird before - perhaps another reason this quiz was tough.  The longish pointed wings and relatively short tail are also typical structural features for this species.

The harder part of this quiz was aging this bird and assigning a name to the plumage.  Now you could have killed two birds with one stone by calling this bird first winter, but the answer I was really looking for was hatching year bird in formative plumage. In other words it has undergone one molt (the preformatve molt) since juvenal plumage.  However, when I made this quiz, I neglected to consider that this bird could be a after hatching year basic plumage female.

Adult birds should have uniformly black, relatively fresh, remiges (flight feathers of the wing; see our old post, "Find the Molt Limit", for bird topography), and a gray back.  This bird appears to have uniformly juvenal remiges, as unlike adult feathers, they are brownish and washed cinnamon.  Assuming that I'm right that this bird is a HY, the remiges are retained from its juvenal plumage, and it has replaced all of its body feathers and so is in formative plumage.  The feathers of the back are are also mostly brownish.  Given the time of year, you can rule out that this is a second year, and you don't even have to worry about alternate plumages (which still look nothing like this).  Ruling out an after hatching year (adult) female is a little more difficult.  This is the only wheatear I've seen, but from a little research it seems like the broad cinnamon edging on the secondaries, brownness of the remiges, and overall buff-brown coloration would be atypical of AHY females.  It also seems that HY birds are far more likely to show up in the continental US than adults.

Still, I don't think I can rule out a female.  After looking more closely at other photos of this bird, I see no indication of any molt limits (which a HY bird should have), and in some photos the wings look very dark brown, which is to be expected from adult females.  Females can also be washed cinnamon, although I believe that this would be on the extreme end.  There is also a decent amount of gray in the back and a lot in the scapulars.  So, since I messed up on this one, I accepted anyone answering Northern Wheatear, regardless of plumage. Comment or email me at with any further opinions on this bird.

Here is another photo of the same bird:
Northern Wheatear, September 2011, Croton, NY [Photo by Lukas Musher]
Ryan Ford
Ryan DiGaudio

~Luke Musher

Wednesday, May 16, 2012

Sometimes Shorebirds Sleep at Night

We spent the entire afternoon and evening at the Heislerville shorebird impoundment mist-netting again today, and had a fairly big day catching about 115 birds in all.  We started around 1:30 and before all of our nets were set up, even, the first birds were hitting the nets.  A steady stream kept coming all day, mostly Semipalmated Sandpipers (SESA), but also a few each of Least Sandpipers, Short-billed Dowitchers, and Semipalmated Plovers.  We also caught a Great-crested Flycatcher, a Barn Swallow, and a Red-winged Blackbird.

We flagged every SESA, and took blood from almost every one as well.  We kept catching birds all the way up until dark, and then had to catch up on banding the last birds.  Although SESAs often get "sleepy" in the hand (not a sign of stress as in songbirds), at night every SESA I flagged basically went right to sleep.  God they're adorable.  This one was sleeping long enough for me to whip out the iPhone for a quick picture.
The overcast conditions today, probably contributed to our large catch, although with 20,000 birds at the impoundment, it was bound to happen.  In the next week or so, we may get as many as 50,000 birds roosting and feeding on the impoundment at high tide, so our catches will get bigger and bigger.
 The sun did come out for a little while though.  Here's a view of our nets from the dike where we band, flag, and take blood from the birds.

 I'm looking pretty cool in my bug shirt and headlamp.  Gotta keep out the mosquitoes and no-see-ums, while flagging in the dark.  By the time we got back it was already past 11:00 pm, then we spun and processed our dozens of blood samples until 1:00am.  What a night.

Monday, May 14, 2012

Photo Quiz

New York in September
Email us at with species, age, and the name of the plumage by Thursday, May 17.  The solution and names of the winners will be posted on Friday.

Sunday, May 13, 2012

Long day of Shorebird Mist-netting

By Luke Musher
Semipalmated Sandpiper, Heislerville Shorebird Impoundment, Cumberland county, NJ

Yesterday we set up mist nets at the Heislerville shorebird impoundments, one of our usual banding locales.  On the bright side, there were thousands of birds, and many more thousands than we've been having at this spot.  The only problem was that they weren't flying into our nets!  We caught 17 birds during our 11 hours (!!!) in the field - 15 Least Sandpipers, and 3 Semipalmated Sandpipers.  Needless to say, we were very bored most of the day.  The highlights were watching World Series of Birding teams rushing by, sorting through the hoards of shorebirds, and taking tons of photos.  

A young South African birder came by and told us about a male Wilson's Phalarope he found. Unfortunately I couldn't leave my post and the bird was in with thousands of shorebirds that were completely backlit for me.  I radioed Tom Magarian, who was at the mist nets across the impoundment, and so in better light.  He was able to locate the bird.  I thought I had the phalarope silhouette for a few seconds, but then lost it after adjusting my scope - rookie mistake.  Shorebirds I did see throughout the day included Black-bellied and Semipalmated Plovers, Greater and Lesser Yellowlegs, Short-billed Dowitcher, Least, Semipalmated, and White-rumped Sandpipers, and three flyover American Oystercatcher.  A Merlin kept the flock moving around for a little while in the middle of the day.  Tom and the rest of the crew on the other side of the impoundment watched it catch and fly off with a peep.
Our nets...without birds in them.
Oh look a flock of 17 Least Sandpiper right by our nets.  None of them got caught.
Fish or American Crow?  A good photo quiz, perhaps. Comment on this post with thoughts. (Hint: look at wing shape)
Least Sandpiper, Heislerville Shorebird Impoundment, Cumberland county, NJ
Black Skimmer, Heislerville Shorebird Impoundment, Cumberland county, NJ
Clapper Rail, Heislerville Shorebird Impoundment, Cumberland county, NJ
Pretty, pretty, pretty cute
So many shorebirds present. Here, mostly Semipalmated Sandpiers and Short-billed Dowitchers with a couple Dunlin and Semipalmated Plovers
Short-billed Dowitcher, Heislerville Shorebird Impoundment, Cumberland county, NJ