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Posts Tagged ‘GPS’

Hello from Petit Manan Island, once again!

The breeding season here on the island has really taken flight since our last post, with the majority of the tern colony having laid eggs, as well as the Puffins, Guillemots, and even some Razorbills! I guess one could say that it is off to an egg-cellent start!

We have been focusing the majority of our efforts every morning on re-sighting birds that have been previously caught and banded either by biologists here at MCINWR, or at other colonies along the Atlantic coastline. We even are lucky enough to occasionally spot birds that were banded along their wintering grounds in Brazil and Argentina. But why is it that re-spotting these birds is so important?

One of the terns we work with, the Arctic Tern (Sterna paradisaea), is quite the world traveler. Once they finish breeding in Maine or along other locations across the arctic, they leave to embark on one of the longest migrations in the bird world, eventually ending up in Antarctica! One bird, tagged and tracked from the United Kingdom, was recorded to have migrated 59,650 miles in one year, making it the longest migration that has ever been recorded. Let me put this straight – this is the equivalent to the bird flying around the world twice, and then adding on another 10,000+ miles. Considering these terns live to upwards of 30 years, this bird will travel farther in its lifetime than most people.

And this is why re-sighting birds is so incredibly important! It not only gives us information like how old the bird is or potentially where it was born, but we can also piece together the puzzle of exactly where each bird travels to during these super long and intense migrations, and more importantly gives conservationists a better idea of which land to protect in order to assure that these birds are around for years to come. Definitely makes waking up at 5 am every morning only to sit in a tiny box for 3 hours a little bit better!

Pictured left to right: A sleepy Common Tern that we identified as an individual banded in Nova Scotia in 2013; Puffin nap time makes re-sighting bands a difficult but adorable job; an Arctic Tern with 2 bands that we identified as an individual born here at PMI in 2016
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Happy band re-sighting!

Best,

Hallie

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It’s time to find out just what our gulls have been up to since we attached GPS tags.  In our first round of tagging, we sent out five tags on five separate Herring Gulls.  The tags we used are useful because they are lightweight, but they don’t transmit the data directly to us. Instead, we have to catch our gulls again.

We started by watching the nest. Both gull parents will help incubate the eggs, trading off throughout the day. The gull not on the nest generally heads out to forage for food. However, we only tagged one gull from each nest, so it’s important that we only set the trap up when the right gull of the pair is taking his or her turn at incubation. Thankfully, the GPS tags are easy to see from a distance.

Once we know the right gull is in the area, we set the gull trap up, just like before. We were hoping they wouldn’t get trap shy and refuse the sit on their eggs when the trap was present. Luckily, our first tagged gull was caught less than an hour after we set up the trap!

Success!

Success! A Herring Gull in a box trap

The tags were removed by cutting off the small tuft of feathers to which they were taped. Don’t worry – birds regularly replaced their feathers, so the cut ones will fall out and be replaced with new ones.

After downloading the data from the tag, what we found was pretty cool: our first gull’s foraging trips were more than 15 miles long. She stuck to the mainland coast, mostly between St. George and Rockland. Her trips sometimes took her more than four hours!

Gull 3 Map

The foraging routes of our first recaptured gull

In the end, we recovered three of the first five tags we sent out, and none of the gulls followed the same paths. One gull went straight up to Warren, ME several times over a few days. That’s a round-trip distance of almost 40 miles. We think he might have been looking for spawning alewives.

Gull 4 Map

Our second gull made a beeline for Warren every time!

The third gull stayed local and barely left the waters around Metinic Island – it looks like she preferred feasting on the spawning polychaete sand worms just offshore.

Gull 3 must have found plenty to eat in her own backyard

Gull 3 must have found plenty to eat in her own backyard

We also lost two tags – the gulls managed to pull them off, so it looks like we need to come up with a new way to attach the tags. Our next step is to design a harness for the tags that the gulls can’t rip or tear. Hopefully we’ll have more news about our wandering gulls before the season is over.

Metinic also has plenty of terns and guillemots – expect to start hearing about them soon!

-Amy

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You’ve seen them on docks. You’ve seen them on dumpsters. They eat fish, french fries, and everything in between. But where do all these gulls come from? And where do they go once they’ve finished their lunch?

 Gulls can be found just about everywhere there’s water (and plenty of places where there isn’t). There are plenty of them around, and they’ve gained a reputation as garbage-eating pests.  But there’s way more to a gull than dumpster diving.

Some gulls, like this Great Black-backed Gull, are actually quite handsome! - Photo by Zak

Some gulls, like this Great Black-backed Gull, are actually quite handsome! – Photo by Zak

First of all, gulls are actually cousins of the terns we’re working so hard to protect out on these islands, and these cousins have a lot in common. Both terns and gulls prefer to nest in large colonies, and lay their eggs in nests on the ground. They’re both strong fliers, capable of traveling long distances over the ocean (although nothing quite tops the pole-to-pole migration of the Arctic Tern).  Males and females of both tern and gull species are almost identical (although males tend to be a little bigger) and both parents work together to raise their chicks.

So why have gulls done so well when terns are in trouble? It all comes down to food. Gulls are opportunistic – they’ll eat anything. Terns are picky eaters – they generally only eat fresh-caught food they pluck from the water themselves. Like a tern, gulls also love fish. But they’ll also eat mussels, urchins, crabs, and in recent years, human refuse. They’ve learned to follow fishing boats, flock to open dumpsters, or sometimes snatch food right out of people’s hands. So gulls have thrived on these new abundant food sources, while terns have been struggling.

A Herring Gull, Metinic's most common gull - Photo by Zak

A Herring Gull, Metinic’s most common gull – Photo by Zak

But we and the Refuge have been wondering, where exactly do Refuge Island gulls get their food? Does a gull here on Metinic fly all the way to the mainland for a meal? Or do they stay local and snack in the intertidal zone? This year is the pilot year of a study to answer those very questions with the help of GPS.

So, what’s the plan?

Step 1: Catch a gull.

The best way to do this is on the nest. The setup is simple enough: the gull sits on a string tied to a wooden prop. The prop separates into two pieces and the box falls down, capturing the gull. We replace the real eggs with wooden ones so they won’t accidentally get crushed. Sounds easy enough, right? Maybe not.

Some people call gulls rats with wings – and it’s not a total misnomer. Both rats and gulls are a lot smarter than many people think.  It took us several hours of trapping to catch our first Herring Gull.

Catch me if you can!

Catch me if you can! AKA, Gulls – 3, Biologist-0

Step 2: Attach a GPS Logger

These little boxes, called igotU tags, are programmed to take a GPS reading every 3 minutes for about 4 days. To attach one to a gull, we put it in a waterproof casing then tape it to the gull’s back feathers with extra strong tape. The tag is light enough that it won’t hinder the gull when it flies, and hopefully the tape will keep the gulls from preening the tag off.

igotU tag getting taped to a Herring Gull's back - Photo by Amy

igotU tag getting taped to a Herring Gull’s back – Photo by Amy

We also band the gull and take a few measurements to determine if it’s a male or female.

Zak checks a GPS tag

Zak checks a GPS tag on a Herring Gull

Step 3: Release the gull!

Amy releasing a tagged and banded Herring Gull - photo by Zak

Amy releasing a tagged and banded Herring Gull – photo by Zak

Step 4: Trap the gull again.

To get the data from the GPS loggers, we have to trap the gull again and remove the tag. Stay tuned for Part 2 to see what we find out!

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A GPS-tagged Herring Gull on its way – Photo by Zak

– Amy

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