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


  1. WOW. Nothing else needs to be said.

  2. sooo many shorebirds... do you guys get dozens in the net at a time? geez :D

    1. Oh and you partly answered my question from the previous post about the blood; so method?

    2. Well, French, it's really quite simple. We poke the brachial vein with a needle and collect blood in capillary tubes. I can't imagine that's different from how you do it. You can see a photo of the grip we use on the bird in "Woosh-netting at Fortescue" (

  3. Thanks everyone. We'll be back at this location to net SESAs this afternoon. Hopefully I'll get some more photos, and maybe even a video of the woosh-net going off.