Almost Paradise: Tortuguero

By Lukas Musher

American Pygmy Kingfisher, Tortuga Lodge, Tortuguero, Costa Rica

This morning while checking nets at one of our sights in primary forest in Tortuguero, it hit me, this is pretty much as close to paradise as you can get.  It began to rain lightly, and the duetting roars of both thunder and howler monkeys echoed around me.  The nets were mostly empty except for an American Pygmy Kingfisher and a White-breasted Wood-Wren.  While extracting the kingfisher, I tried not to flinch as the tiny pricks of mosquitoes drawing blood plagued my hands and face.  As they gorged and I fiddled with the bird trying to figure out the secret to its removal, my mind went blank as I finally couldn't take the agitation any longer, letting go of the bird with one hand to slap the mosquitoes from my cheeks and neck.  My hand returned to the bird, now with bright red stains and minuscule black lines that once were legs.

Wedge-billed Woodcreeper, Tortuga Lodge, Tortuguero, Costa Rica

No, it wasn't perfect, or comfortable, or luxurious by any means, but there is something about this crazy place that has held a particularly special place in my heart (and in my brain; I find the tropics fascinating) since I first visited the tropical rainforest as a young teenager.  Droplets of sweat, like condensation on a cold bottle of water, littered my forehead and upper lip.  I breathed slowly, trying to block out the dizziness and slight headache from dehydration.  I know it sounds horrible, but it truly is an amazing place.

Purple-throated Fruitcrows began calling above me.  The female flew over and paused to stare with nesting material in her mouth – a life bird.  Somewhere not too far away a Laughing Falcon began calling, guaco guaco guaco, over and over.  Tiny poison dart frogs, bright red with blue hind legs (called bluejeans frogs) jolted spasmodically over the leaf-covered forest floor.  Finally the bird was out.  I put it in one of our cloth bags and tied the draw string, then returned to the banding station.

Female Purple-crowned Woodnymph, Tortuguero National Park, Tortuguero, Costa Rica (iPhone photo)

Since I got to Tortuguero 5 days ago I've seen and done a lot.  Although it rains a lot, and I haven't been able to get too many photos, we've caught all kinds of interesting species, and seen some cool birds.  Gartered and Slaty-tailed Trogons, Keel-billed and Black-mandabled Toucans, Mealy and Red-lored Parrots, Black-cowled Oriole, and lots of other species have been seen regularly.  On the boat ride here we saw an adult and juvenal King Vulture.

Grayish Saltator with an interesting molt limit in the remiges (flight feathers of the wing).  Notice primaries 1-3 and secondaries 1-3 are retained.  This bird is a member of the family, Cardinalidae, related to grosbeaks and cardinals.  Not sure why it would show eccentric molt like this.  The other wing showed molt in primaries 1-3 and secondaries 2-4.  The tropics are crazy.

Banding has been slow, and we've had some trouble opening nets due to rain, but the birds we catch are quite special and interesting.  Hummingbird captures have included Blue-throated Goldentail, Rufous-tailed Hummingbird, Bronzy, Stripe-throated, and Long-billed Hermits.  White-capped Manakins are our most common species and well-studied by CRBO biologists.  Other cool captures here have included Wedge-billed Woodcreeper, Great Kiskadee, Common Tody-Flycatcher, Grayish Saltator, among others.

Juvenal Bare-throated Tiger-Heron, Caribbean Conservation Corporation, Tortuguero, Costa Rica

Pale-vented Pigeon, Caribbean Conservation Corporation, Tortuguero, Costa Rica

WEWA at Palo

Worm-eating Warbler, PRBO Palomarin Field Station, Bolinas, CA 6/10/12 [Photo by Mike Krzywicki]

On June 10, the banding interns at the Palomarin field station caught this awesome Worm-eating Warbler!  Just thought I should share it.  There has also been a Black-and-white Warbler hanging around.  Wish I was still there to experience this rare vagrant.  The last time this species was captured at Palo was in 1979.  Thanks, Mike and Laura for banding and sharing this cool bird!

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, bandedbirds.org.  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

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.

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

Woosh Netting at Fortescue

By Lukas Musher

Paris getting ready to take blood from this Short-billed Dowticher [Photo by Luke Musher]

As many of you know, I've recently started a job banding shorebirds for NJ Audubon.  On Wednesday we set up a type of net called a woosh net with the hopes of catching our first Semipalmated Sandpipers (our main study species) of the year.  Although there were several hundred shorebirds (will soon be a few thousand) present, we only caught about 20 Short-billed Dowitchers and 2 Dunlin.  Not too bad.

There are tons of horseshoe crabs spawning on the bay shore right now, and Fortescue is a good place to watch.  While they're spawning the shorebirds and gulls are present in large numbers.  Yesterday there were Least and Semipalmated Sandpipers, 2 Red Knot, Semipalmated and Black-bellied Plovers, Sanderling, Dunlin, and Short-billed Dowitchers including a beautiful hendersoni.

[Photo by Bruno Almeida]

Woosh nets operate a lot like a cannon net, except that it is fired by bungee chord instead of by cannon.  Two poles are stuck into the sand and act as a guide for the net when it is fired.  When the birds get within range of the net it is fired by pulling a string that pulls pins our allowing the bungees to release.  Watch: 

[Photo by Bruno Almeida]

[Photo by Bruno Almeida]

[Photo by Bruno Almeida]

[Photo by Bruno Almeida]

FIRE! [Photo by Bruno Almeida]

[Photo by Bruno Almeida]

[Photo by Bruno Almeida]

Two Shorebirds

By Luke Musher
Our first day in the field for my shorebird technician position was slow (and buggy!!!) today, but at least we got to handle two species.  The first bird was a Least Sandpiper, and the second was a Short-billed Dowitcher.  Check it -

Expect more of this soon.  We should catch upwards of 1500 Semipalmated Sandpipers by the begining of June along with Dunlin, Semipalmated Plover, and these two.  There's always the chance of Curlew Sandpiper at Heislerville!

Red-shouldered Hawk Indeed: Gawk at this Hawk

Three days ago we had a post about one of the two Red-shouldered Hawks we caught this past week.  The second hawk, to us banding amateurs with little hand-hawk experience, looked odd especially compared to the first bird we caught (read first RSHA post).  It had features that reminded us easterners of Broad-winged Hawk.  Look at the photos here and see what we mean.  Turns out, after running it by the hawk banders at Golden Gate Raptor Observatory, the bird is definitely within the normal range of variation seen in the California Race of Red-shouldered Hawk, Buteo lineatus elegans.  Here are some photos taken by Dan Lipp of the overzealous Frenchie holding this beautiful SY RSHA.  

This photo shows the pale grayish brown eye that is typical of a young Red-shouldered Hawk.

An adult California Red-shouldered Hawk would show a nearly solid orange breast with an orange belly with white barring. The brownish barring on this SY RSHA is very reminiscent of a Broad-winged Hawk, and it has a much smaller, streaky bib than our previous SY RSHA. However, this RSHA's plumage is within the normal variation one could expect to see within the California subspecies.

Here you can see the tail with fewer, thicker bands than our first Red-shouldered Hawk, but the California subspecies immature can show a more adult-like tail than the eastern subspecies. 

By Luke Musher and Cory Ritter

More Like Boom Red-shouldered Hawka

Generally speaking, only birds up to a certain size will get caught in mist-nets meant for trapping passerines.  That size constraint is usually around the size of an American Robin, or the occasional male Sharp-shinned Hawk--as you have seen.  Birds that are any larger will usually not get tangled in the small-sized mesh of the mist-net, and are able to free themselves with a little struggle--or simply break through the net if large or strong enough.  So then, on Saturday, Dan and Cory were pleasantly surprised when they were on the closing net run and came upon this SY Red-shouldered Hawk in one of our nets. It was barely caught, so we were lucky that she didn't free herself before Dan and Cory were able to grab her. 

SY female Red-shouldered Hawk

Luke and the RSHA

Dan with the RSHA. They both look pretty confused.

Cory and the RSHA

After processing and banding the bird we did a quick search through PRBO's data and found that there have only been nine individual RSHA banded at Palomarin in the forty-six years of its existence, and only 12 captures total (i.e. some were recaptures of the same individual).  We are pretty lucky.  Even luckier was the fact that yesterday Dan and Frenchie caught another most likely second year RSHA, this time a male, at one of our offsites, Pine Gulch.  That makes two RSHA in three days (needless to say Cory and I were pretty jealous)!  To make matters more interesting, the bird has features that are quite similar to Broad-winged Hawk.  We are currently trying to confirm this bird's identity, and although we are leaning towards RSHA, it is certainly an interesting bird.  We will have more on this within the next few days.

By Cory Ritter and Luke Musher
Photos mostly by Dan Lipp