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Posts Tagged ‘Trapping’

So far around the island we’ve come across Common Eider, Mallard, Savannah Sparrow, and Spotted Sandpiper chicks. Although a little behind schedule, we were beyond happy to finally find our first Common Tern chicks! Soon we will start banding them and taking measurements. Hopefully we will start seeing more every day!

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Our first Common Tern chick!

Our terns have been acting different than normal. Rather than settling down to incubate, many of them appear to be much more active flying around and leaving the island. We grew suspicious that there might be an owl around. In order to make sure it doesn’t disturb our terns, we set up a total of 17 foothold traps covering all sections of the island. When we placed the traps, we put them in areas that seemed suitable for an owl to land. If the owl lands on the platform that contains the trap, its leg will be caught. This trap doesn’t hurt the owl because it’s padded, but it allows us to capture it so it can be relocated. Though our minds were focused on an owl, we didn’t forget about our frequent Peregrine Falcon visitors. To prevent any unintended capture, we made sure to set off the traps during the day.

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The sign is lined with chicken wire at the top making the post with the trap the only suitable place to land

Only a few days after setting the traps, we caught the owl! Morgan and I noticed the terns were once again acting strange during our night stint, where we took shifts watching the colony between 6:00 PM and 12:00 AM. The next morning the terns were dive-bombing at the ground, and I could see through my binoculars that the trap wasn’t on the post anymore. It seemed unlikely that we caught an owl, especially since we weren’t completely sure we even had one, and last year it took over 2 weeks to catch it! We walked over expecting to find something like a gull caught up in our trap, but to our surprise it was a Great Horned Owl! We safely caught the owl, covering its head so it would stay calm, and removed him from the trap. It already had a band on its leg, so we suspect that it might be the same one from last year. The owl will be brought to a rehabilitation center to make sure it isn’t hurt, and it will be released somewhere far from our terns! We are so thankful we caught it in time, especially now that our eggs are hatching!

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Morgan about to cover the infamous Great Horned Owl with a blanket to keep him calm

 

Outside of bird research, we enjoy watching the Harbor Seals bask in the sun and swim around with their pups. The seals can be found on two adjacent islands. One pup decided to visit us on Ship this week. We were nervous when we didn’t see the mom around, but we were taught that after 3 weeks the pups begin to live on their own.

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Curious pup visiting our island

Ship has been very busy this week. We’re hoping to continue to wake up to new surprises every day, but only good ones!

-Amanda

 

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The beginning of the week started out slow and rough as the weather was not cooperative.  High winds made it so we could not go out to the tern colony as we wanted the adults to stay on their eggs and keep them warm from the howling winds.  Finally the weather broke Tuesday afternoon and we were able to do some trapping and banding of adult terns.  We do this by selecting a couple of nests, replacing the eggs with wooden ones so they do not get damaged, and placing a chicken wire trap over the nest with the door open.  When the adult walks into the trap, they step on a trigger platform that closes the door.  As the adult sits in the trap incubating the wooden eggs, we walk up and take it out of the trap through a hole in the top.  The adult is then placed in a bag where it is weighed using a spring scale.  We then band the bird and measure its wing chord and head-bill length before it is released to return to incubate its eggs which we have switched back to the real ones.

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A common tern checking out the trap

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Measuring wing chord length

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Measuring head-bill length

Wednesday we headed over to Matinicus Rock to help them with their tern census.  It was nice to get out to another island to see what was going on there; plus we got to see Atlantic puffins, razorbills, and common murres, three species that do not nest on Metinic.

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Atlantic puffins on Matinicus Rock

The next day it was our turn to census!  With the help of a few guests, we were able to count 608 nests in our colony of arctic and common terns!  We did this just in the nick of time as we came across multiple hatched chicks with more popping up every day!  The rest of the week was spent securing our productivity plots which are circles of fencing surrounding a number of nests.  When the chicks within the plots hatch, we record the hatch date and band them.  Every time we visit the plots, we weigh the chicks and keep track of how they are doing until they fledge.

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Pipping arctic tern egg

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A hungry chick waits to be fed

Throughout the week we have also come across savannah sparrow chicks and fledglings, and spotted sandpiper chicks running around on the rocks.  An identifying characteristic of spotted sandpipers is they bob their rump up and down as they walk; it is funny to watch the tiny fuzzy chicks do this as well!  We are looking forward to more chicks showing up in the upcoming weeks!

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A tiny spotted sandpiper chick

Until next week,

Helen

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While most of the other MCINWR islands are winding down for the season, Petit Manan is still going strong with major alcid trapping, island-wide guillemot and storm petrel checks, Arctic tern re-sighting, and our new-this-year project: Atlantic puffin feeding studies.

Atlantic Puffin with bill load

Atlantic Puffin with bill load through scope.

Puffin flying to burrow with fish that we have to identify as part of our feeding study

Puffin flying to burrow with fish that we have to identify as part of our feeding study

During our alcid checks, we discovered two little surprises in the form of Razorbill chicks! Only five pairs are breeding here on Petit Manan, so each new chick is very special to us. We even managed to capture one of his parents bringing food back to the burrow, an unusual sight here on PMI

Freshly banded Razorbill chick

Freshly banded Razorbill chick

Razorbill flying with food

Razorbill flying with food

Here are a few more snapshots of what else has been going on at PMI.

Black Guillemot chick being weighed during our weekly productivity checks

Black Guillemot chick being weighed every 5 days as part of our productivity checks

Leach's storm-petrel chick

Leach’s storm-petrel chick

PMI crew banding a puffin chick, minus Julia who took the photo

PMI crew banding a puffin chick, minus Julia who took the photo

A puffin undergoing the banding process

A puffin undergoing the banding process

Wayne and Julia with their first captured adult Razorbill!

Wayne and Julia with their first captured adult Razorbill!

Until next time,

Wayne and Julia

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Last week, John and I trapped and banded our first terns! We were thrilled to finally have the opportunity to see and work with these birds up close. But these amazing up close interactions did not come without a lot of hard work and preparation.  The process of trapping and banding is very detailed and a complete understanding is needed to keep the terns happy and healthy.

Before we could start banding, Julia and Wayne had us practice on dummy birds. These dummy birds were composed of cardboard toilet paper rolls for bodies, Q-tips for legs, and duct tape for heads. Julia and Wayne informed us of the methods of handling and banding terns when out in the field and with their help we simulated banding on our dummy birds by using old bands. After we felt comfortable with banding we learned how to collected measurements from our birds. When a tern is captured we recorded the weight, wing length, and head and bill length of the tern. We got to see and use all of the tools used to take these measurements.IMG_8528

In preparation for trapping, we laid out all of our equipment out on the lawn and checked to make sure all of the traps had all their components and were functional.  John and I spent some time getting used to setting up the traps and gripping the idea of the little quirks that makes the trapping process run a lot smoother.  Once we were quick and efficient with setting up out traps we were ready for the real deal!

Laura & Julia setting up their trap

Laura & Julia setting up their trap

Our first trapping day was nerve racking and exciting! We had to find a balance when trapping and banding our terns that would enable us to work fast but also be gentle and thoughtful when handing the terns. As much as we wanted to take our time and soak up all the beauty, we had to act quickly and efficiently when banding the terns to minimize the amount of stress placed on the birds. I felt uneasy going into my fist banding experience; this wasn’t like the dummy birds we practiced on, the terns move around a lot more than the dummies and one wrong pinch on the band could harm the tern. But to my surprise banding my fist bird came natural to me and it went smoothly. I got to trap and band many more terns that day and I hope to do some more in the next few days.

John and his tern

John and his tern

So far we have trapped 19 COTE (common terns) and 16 ARTE (arctic terns) our goal is to have a total of 20 COTE and 100 ARTE by next week! Trapping and banding terns is important because it shows sight fidelity and survival rates of juveniles and adults.

– Laura Bollert

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For the past few weeks, a lot has been going on with Petit Manan’s tern colony!  We have been focusing much of our time on trapping and banding both Arctic and Common Tern adults, which is an essential part of our research.

In order to capture terns, we use two types of traps—the bownet and treadle trap—to catch adults on their nests.  First, we temporarily remove the eggs from the nest so that the bird does not crush its eggs if it struggles in the trap.  The real eggs are replaced with painted wooden ones, and a trap is set over the nest. Trappers then hide out in a blind and wait for terns to return.

The bownet is a spring trap that is set behind the nest cup and triggered when the adult sits on two monofilaments stretching over the “eggs.”  This trap has a metal frame and netting which springs harmlessly over the bird to contain it.  The treadle is a small cage trap with a door, which the tern must walk through to trigger its closing mechanism.

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a Common Tern being removed from a treadle trap

When a tern is captured, a researcher runs out from the blind to retrieve it and replaces the fake eggs with the real ones.  Each tern receives a metal band with a unique number on one leg.  Every Arctic tern also receives a field readable band with an alphanumeric code on the other leg, so that it can be easily resighted from a distance.  We take several measurements, including mass, wing chord (wing length), and head/bill length before releasing the tern.

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Julia banding an Arctic Tern

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Wayne releasing an Arctic Tern

By banding these birds, we can learn about their migration paths, longevity, nest site fidelity, and productivity.  Banded birds may be re-trapped or resighted in the future.  If a banded bird is found along its migration path or on wintering grounds, we can learn about where it has been travelling.  If a bird that was banded as a chick is later found as a nesting adult, we know that it has lived to breeding age and laid eggs.  Speaking of chicks…

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first Common Tern chicks hatched on 6/20

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first Arctic Tern chicks hatched on 6/22

We found our first tern chicks of the season on June 20!  Every day we are finding more chicks, and banding them as well.  As the season continues, we will be closely monitoring their growth, survivorship, and diet to learn about the colony’s overall health.  Stay tuned for more posts about these little cuties!

-Anna

 

 

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Arctic Terns have arguably the most impressive migration of any bird – they travel from the Arctic to the Antarctic and back again just about every year of their lives.  While we’ve known for a while where the terns travel, how they get there has been something of a mystery. Do they travel along the coastline? Do they take a direct route from Maine to the Antarctic coast? Do they do a marathon flight from pole to pole, or make pit stops along the way?  These questions were nearly impossible to answer until very recently, for the simple reason that following a single tern (or even a flock of them) is nearly impossible. Terns are small birds – a little over 100 grams, or 3.5 ounces – so they can’t be equipped with heavy satellite tags. They also do mostof their traveling over water, so the odds of spotting a tern on its migration are slim.

Enter the light-level geolocator, here to solve these problems and answer many of our migration questions

A geolocator, wrapped in a waterproof cover, attached to the leg of an Arctic Tern

A geolocator, wrapped in a waterproof cover, attached to the leg of an Arctic Tern

Four years ago, in the summer of 2010, the Refuge deployed 30 geolocator tags on 30 separate Arctic Terns. These tiny tags are lightweight enough that they don’t hinder the terns as they travel (in fact, they’ve been used on even smaller birds, like Purple Martins). They work by using detecting light levels and recording the time of sunrise and sunset every day. Since the length of day and the time of sunrise and sunset are slightly different at every point on the globe, this information can be converted into a rough map of everywhere the tag, and by extension the tern, has been.

A pretty miraculous little gadget, isn’t it? But there’s a catch: to reduce weight, the geolocators don’t transmit the data they gather, they simply record it. To get at all that information, the tag must be retrieved and physically attached to a computer. This means the tagged birds must be recaptured and the tags removed before they do us any good.

A geolocator (right) and a field-readable band (left)

A geolocator (right) and a field-readable band (left)

Recapturing a bird can be difficult. The best way to do so is to find the bird’s nest, and use a trap that springs while the bird is incubating. That, however, requires the bird to be able to find a mate. Last year on Metinic, Zak and I spotted a geolocator-equipped tern who had eluded capture for 3 years, but we couldn’t get our hands on him because he didn’t have a mate or a nest.  He spent all summer trying to court various female terns with fish, but there were no takers.

Hard to believe such a good-looking guy couldn't find himself a date

Hard to believe such a good-looking guy couldn’t find himself a date

This year, our lonely tern returned and found himself a mate. Syd and I set up a trap called a bow net trap, which is triggered by the tern attempting to incubate a set of fake wooden eggs (the real ones are safely stored in a blind so they aren’t crushed by a struggling tern). It took a couple of tries, but today we succeeded in capturing the handsome gentleman we have nicknamed Giovanni (Geo, for short).

Syd and Geo

Syd and Geo

Geo was released back to his mate and eggs, probably glad to be rid of his extra baggage. The geolocator will be returned to Refuge staff, who will hopefully be able to use it create a roadmap of Geo’s travels from the past four years. That could be up to eight traps between Maine and Antarctica – more than 70,000 miles!

Geo, free of the geolocator and sporting a shiny new band

Geo, free of the geolocator and sporting a shiny new band

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Although I may have spent the first few posts talking about songbirds and gulls, terns are our focus around here. These feisty seabirds are what bring us to Metinic, so it’s high time I let them have their “tern” as the center of attention.

Metinic’s terns, both Common and Arctic, had a rough season last year. Because of an unfortunate combination of bad weather and lots of egg-eating gulls, the terns were forced to abandon their nests shortly after they began laying eggs.

A Common Tern soars over Metinic - Photo by Zak

A Common Tern soars over Metinic – Photo by Zak

We were all holding our breath to see if the terns would take a chance on Metinic again this year. Even if they did, we had no idea how many would actually return.

After completing our annual tern census this week, we’re pleased to say we have 350 pairs of terns nesting on Metinic this year!

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An Arctic Tern on the nest – Photo by Zak

We’ve also had chicks of both species start hatching – more than fifty of the island’s most adorable residents have popped out of their shells. The adult terns are already hard at work bringing in enough fish to feed their new chicks. It will be about a month before these little fluffballs are ready to fly, so the adults have their work cut out for them.

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An Arctic Tern brings back a fish for its chicks – Photo by Zak

These days, Zak and I are out banding chicks in our productivity plots so we can chart their growth. Unlike tern parents, we can’t tell chicks apart without some kind of marker, so all productivity chicks are banded within a day or two of hatching.

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Amy banding a tern chick – Photo by Zak

We’ve also been trapping and banding adult terns. As with gulls, the best way to trap a tern is on their nest. We replace the eggs with wooden dummy eggs and set a trap that springs when the adult returns to incubate. We then band the tern and take a few measurements before releasing it. The dummy eggs are removed and the real ones are put back in the nest.  The terns aren’t too happy with the process, but they always seem to return to the nest within 15 minutes of being released.

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Banding an adult tern – Photo by Zak

By banding adult birds, we have a better chance of seeing the bands again – any breeding adult has already proven its ability to survive at least one migration, so it’s likely that it will survive another year. Some terns can live to be more than thirty years old, and every time we see the band we add another piece of information about that bird’s life.

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An Arctic Tern – Photo by Zak

You may notice us wearing some strange looking hats in our photos. While we’d like to pretend these are the very latest in high fashion, they’re actually a practical method of tern defense. When protecting their nests, adult terns aren’t afraid to peck an invader, be it gull or eagle or human, on the head. They typically aim for the highest part of the body, so adding a flag to the top of you hat is a good way to keep your head from getting pecked.

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Tern attack! Adult Common Terns defend their nests from an invading mammal (aka Amy) – Photo by Zak

We’ve got a few more terns stories coming up, plus an update on some of our other seabirds, like Black Guillemots and Leach’s Storm Petrels, so stay tuned!

-Amy

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