Tuesday, May 20, 2014

The Real Pirate of the Caribbean

Our next day on the Caribbean coast was primarily for fishing - trying to land one of the monster tarpon that can be found in Costa Rica's tropical waters.  The remote waterways between Tortuguero and the Nicaraguan border to the north also harbor some great birditat, so I was hoping I could also spot some good birds along the way.  Our destination was the mouth of the Colorado River (no, not that Colorado), where it empties into the Caribbean Sea.  To get there involved transiting miles and miles of narrow canals, dug a century ago by logging companies.  The jungle has since reclaimed this vast, remote swath of tropical lowlands.  Huge palms lined the shores.  Parakeets and Montezuma Oropendolas flew back and forth across the shallow waters.  A few Dusky-capped Flycatchers, a lifer Myiarchus, sang from the snags near the bank.

We started moving into progressively larger bodies of water.  I spotted a few small groups of Groove-billed Anis, all-black relatives of cuckoos.  Finally, we rounded the bend to see the wide, muddy Colorado stretching before us.  We headed past basking American Crocodiles, just feet away from feeding Little Blue Herons and a Roseate Spoonbill.  

The first spot we tried was a bust - no fish were biting.  This was also the first time I truly experienced the sweltering tropical sun.  I actually felt like I was melting.  Luckily for me, we pulled anchor and went downstream to the river mouth.  Here there was at least a breeze - but any relief I felt was soon crushed by the huge swells coming in off the sea.  Not good news for someone who gets seasick.  We were in a pretty small boat, and the water was just a few inches from spilling over and sinking us as each wave went by.  My dad and I were legitimately worried by the time our guide Roberto dropped anchor.  Pretty soon, though, 100+ pound Tarpon started biting, and we pretty much forgot about the waves.  We couldn't keep any of them on for long - we weren't exactly experienced with fish nearly the size of a person!

There was a lull in the action, and I looked around me.  A sizable flock of Royal Terns were resting on the beach on the south side of the inlet.  To my surprise, they all took off.  I spun around to see a powerful gull-like bird barreling toward the terns at top speed.  It was mottled brown with striking white patches on its inner primaries.  I knew what it was, a bird I had never seen before.  A jaeger.

Hell yes.
"Skua!" Roberto shouted, "that bird belong WAY out in da ocean."  He was right.  Parasitic Jaeger (called Arctic Skua in many parts of the world) was just about the last bird on my mind at the time.  It wasn't even in the field guide I brought along.  I jumped down to grab my camera, and started firing away.  I knew the only way I would be able to safely identify the bird to species would be with photographs, especially considering my lack of experience with the genus. (Note - I am pretty sure about my ID, but if anyone disagrees, feel free to comment below.  Jaegers are hard.)

The word "jaeger", used in North America to describe the smaller species of skuas, comes from the German word "j├Ąger", or "hunter".  It's not really an accurate name - this bird doesn't do as much hunting as its name suggests, at least not in winter (they feed on smaller birds more frequently in summer).  In fact, it gets most of its food by stealing from other birds - a habit known as kleptoparasitism, the natural world's equivalent to piracy.  Jaegers chase and harass their victims, particularly gulls and terns, until they give up whatever prey they may have caught.  It's awesome.  I watched this particular bird bolt after the flock of terns, singling a few out to target at a time.  It clearly had an upper hand with its freakish speed.  After just a few minutes at the inlet, this avian pirate turned back to the sea, and melted away into the horizon.
Parasitic Jaeger flying over the rainforest - not a caption I ever thought I'd write.
This was the highlight of my day (my dad's highlight was catching a 100 pound tarpon - I failed to land one).  On the way back, Roberto did find one more nice surprise for us - a slightly out-of-range Snail Kite perched above a backwater.  It was pretty cooperative, though the heat shimmer made the photo a little blurry.
Snail Kite - a kite that eats snails.
We finally got back to the lodge around mid-afternoon, finishing up the boat ride with a group of White-collared Swifts circling overhead.  It had been a fantastic last day in the lowlands - our next destination would be completely different.

2 comments:

  1. I'm no jaeger expert either, though I have seen both Pomarine and Long-tailed Jaegers. Your bird is DEFINITELY not a Pom Jaeger; it's too slim winged and not bulky as in typical Poms. I've actually never seen a Parasitic Jaeger, but I've heard they average smaller, slimmer-winged, and less bulky than Pomarine Jaegar. Finally, Long-tails are very slim-winged compared to the other jaegers and overall smaller. I don't know if you own the Kaufman Field Guide to Advanced Birding but has a nice section on jaegers (though it doesn't seem to stress the importance of shape/structure enough). On page 310 it shows juvenile jaegars and your bird looks a lot like a Long-tail. His discription on pg 311-312 says some juvenile Long-tailed Jaegers have pale (almost white) heads, a very light colored belly, and black and white bars on the uppertail coverts and undertail coverts. Your second photo also appears to show a very slim-winged bird, but that may just be the angle.
    With that being said, consider Long-tailed Jaeger as a possibility. But don't rely on my thoughts! Show it to an expert if you get a chance or haven't already.

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  2. Yeah, I was stuck between Long-tailed and Parasitic for a while. I was spending hours looking at incredibly variable plumage details trying to decode this bird, but I realize now (after seeing both Long-tailed and Pom Jaegers this weekend) that shape/structure is what is important here. Long-taileds seem much "daintier", for lack of a better word, than this bird. Also, Long-tailed bills seem to be much narrower toward the base, whereas this bird has a heavier, more Pom-like bill. The flight style was most similar to that of a Peregrine Falcon, not really like the buoyant, graceful, and shallower wingbeats of the Long-tailed. Long-taileds, to me, give the impression of having proportionately larger eyes compared to the head than this bird has. I was glad to look back over this after seeing the other two jaeger species in the field - but I came to the same conclusion of Parasitic (they also are much more likely to come to shore). Tricky IDs are part of the fun, and immature jaegers are pretty much as tough as it gets.

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