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Posts Tagged ‘Common Tern’

While walking through Ship Island’s colony, I’m always fascinated by the variety of egg shapes and sizes we come across. Out of curiosity, I decided to measure and photograph some of these eggs to see how variable Common Tern eggs can be!

Eggs are developed rather quickly. After copulation, an egg can form and be laid in 24 hours! Typically, an egg can be added to the nest every 1 to 2 days. While most clutches contain 1-3 eggs, this season, we’ve found some with 4 to 5! The nest starts off as a simple scrape in the sand, gravel, or dirt. As parents spend more time around or in the nest, they’ll move twigs, vegetation, seaweed, and other objects around to create a proper nest that will keep their eggs inside.

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A Common Tern nest with 3 eggs

On average, Common Tern eggs are 42 mm long and 30 mm wide. As always, there are some eggs that do not meet these parameters. I found that lengths vary the most, ranging from 38 to 46 mm! Meanwhile, egg widths stay closer to the average, varying from 28 to 31 mm.

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These two differently sized eggs are from the same nest!

Tern eggs are subelliptical meaning they are elongated with tapered rounded ends. The widest point of the egg is off center. Like size, shape varies greatly! Some eggs have the widest point towards the middle, creating an oval shape. Others have the widest point so close to one end, the egg has a long narrow point, like a raindrop.

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A typical, subellipitcal egg

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Almost an oval-shaped egg

Sometimes, the most striking feature about the egg is its color and pattern. In just one clutch, the eggs can look wildly different. The colors can range from cream, tan, light brown, to dark brown. The shells are covered in small to large dark splotches and streaks. These markings can concentrate around the widest point, like a belt, or spread across the egg like freckles. The color and pattern is thought to help camouflage the eggs on the beach. However, we occasionally find some odd eggs that stand out. Some appear almost pure white with faint or no markings at all! Others are so dark brown that the markings are hard to distinguish.

Although Andy and I love finding these eggs, we’re hoping that they’ll be hatching soon! While there are some eggs which have been freshly laid, there are some which have survived abandonment and could be hatching any day. We look forward to welcoming the first chicks to Ship!

Percy

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Greetings from Metinic! We’ve had foggy weather this past week and only two days of full sun.

I thought I would take this opportunity to share what daily life is like on Metinic Island. You may be wondering, “What do they do in their free time?”, “What do they miss most about civilization?”, or, “Do they even miss civilization?” Hopefully this will provide some insight into what it’s like to live in a seabird colony.

Every morning at 7 o’clock we start the day by counting all of the birds seen around the island, including shorebirds, passerines, and raptors. Daily tasks in the tern colony vary week to week but recently we have been closely monitoring our productivity plots to check for newly hatched chicks; banding, weighing and measuring each one to track growth rates.

When the weather isn’t on our side, we find ourselves cabin-bound. This is a good time to catch up on data entry, read a book, and wonder, was it the tern or the egg that came first? We have a solar panel that provides us with electricity and a propane stove to cook on. Although we don’t have running water, we are supplied with drinking water from the mainland and we use well water for showers and hand-washing. To make showering possible, we heat up a solar shower bag in the sun and it’s (almost) as good as a real shower.

By the time the sun is setting, we’re usually ready for bed. Every few days we take turns doing a hour-long “night watch” where we use night-vision binoculars to watch for predators in the colony. This is a good time to observe the storm-petrels flying around the cabin and the starry night sky.

To answer my own question posed earlier, we’d say the things we miss the most are hiking, our pets, and moving at speeds faster than a sheep-chasing jog. Despite these things, neither of us are looking forward to returning to civilization at the end of July, even for a hot shower or a car ride.

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Emma banding a tern chick in one of our productivity plots.

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A common tern overseeing the banding process from Sequoia’s head.

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Strange cloud formations passing over the island.

 

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Hello from Metinic!

Sequoia here with this week’s blog. Last Wednesday the 17th we had staff come out to the island to assist us with the GOMSWG census. During this census we identified all nests in the colony. This year we counted 910 tern nests, this is a record for Metinic! This number is also lower than the actual nests present because no matter how hard we try we aren’t perfect at detecting nests. To account for error we use the Lincoln Index which is a form of mark recapture, where we go out and see what percent of the nests were missed. Once this correction was applied we have an estimated 1,021 nests on the island!

We also had some exciting things happen during our census. We found a Leach’s Storm-Petrel, a Savannah Sparrow chick evading a snake who had already caught its sibling, and a few Spotted Sandpiper chicks running around on their stilt-like legs.

Other exciting news, we had our first chick hatch on Friday! An Artic tern chick was the first to be found in our productivity plot. We nicknamed him Eddy due to the fact that Eddy Edwards, the Deputy Refuge Manager, had the closest guess to the number of nests on the island, which we all thought was a bit high but were proven wrong. Friday afternoon and into the weekend we had many chicks hatching, so now we are getting into the grove of weighing, measuring and banding each chick in our productivity plots.

Through all of our adventures we are sometimes lucky enough to be fueled by the homemade snacks that Carol sends out to us, which we greatly appreciate!

Until next time.

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Common Terns tend to be the more tenacious nest protectors. This photo was taken while measuring chicks and getting hit by the parents.

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This is a good example of Garter Snake predation on Metinic. It’s munching on a unlucky Savannah Sparrow chick. We’ve sent 31 snakes back to the mainland so far this year.

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“You can’t see me”

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Eddy, our first chick on the island. Here he is 24 hours old.

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While the other islands are expecting their first chicks any day, we watched as all of our terns left their eggs behind. We were hopeful this year! We had over 100 nests and over 200 eggs. Yet, once again, Ship Island has experienced a colony abandonment!

During the first week of June, we had found some predated terns, likely due to a Peregrine Falcon. Ship is located only a few miles from Mt. Desert Island where several pairs are known to nest. Our worst fears were confirmed when Andy and I both flushed the falcon on June 8. As the day went on, tern numbers decreased dramatically from 300 to 50. By the evening, they were all gone.

We weren’t just only concerned about Ship. Over on Trumpet Island, there were no gulls. A predator like a falcon wouldn’t cause the gull colony to abandon as well. We began to suspect an otter attack. Although the gulls eventually returned to the island, we visited the following day to look for predation signs. We were relieved to find nests and eggs intact. We even found some newly hatched Herring and Great Black-backed Gull chicks! However, we think we now know the likely culprit: an owl.

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We got right to work, setting up more traps and beginning all night stints. But, what do we do to encourage the terns to come back? Since terns nest in colonies, they won’t nest if there aren’t others terns around them. So, we have to trick them into thinking there are terns there already!

Currently, there are over 30 Common and Roseate Tern decoys around the nesting grounds. To complete the illusion of a lively tern colony, a solar-powered sound system has been set up. During the day and night, we play recordings of a colony on speakers.

Although we haven’t caught our owl yet, we think the decoys are working! Throughout the week, we’ve seen more terns returning and staying longer. Just today, I even witnessed courtship rituals and nest scraping! We’re doing our best to give them space to allow the colony to start back over.

Hopefully next week we’ll have some better news to share!

Percy

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Hello everyone!

This is Emma updating you from Metinic, where we’ve been enjoying the plentiful amounts of sunshine over the past week. With increased temperatures comes layers of zinc sunscreen, great laundry weather, and daring plunges into 50-degree Maine waters after long workdays in the sun.

The birds also seem to be enjoying the good weather. This past week we set up our productivity plots with help from the Refuge staff. Using these plots, we hope to monitor at least 60 total Arctic and common tern nests throughout the season for different factors of reproductive success, including hatching success, survival, and growth of the chicks over time. Although we don’t have chicks yet, we are expecting our first one within the next week!

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Recording data in one of our productivity plots.

As the common eider eggs hatch, we continue to see common eider crèches (groups consisting of hens and ducklings) around the island. We have also been monitoring spotted sandpiper and black guillemot nests. The spotted sandpipers nest in low vegetation along the shoreline and in the upland areas. The parents do a great job hiding the nests and it’s easy to miss them if you’re not looking carefully! The black guillemots nest in burrows along the coastline, which makes for fun but challenging work trying to locate them. It really puts our rock-climbing abilities to the test. The overall variation in egg size and coloration among species is really fascinating and beautiful to see.

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Can you guess who these nests belong to?

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The excitement of finding a black guillemot nest!

I enjoy seeing the many flowering plants on the island as the season progresses. Just yesterday we came upon a patch of blooming irises! We also don’t mind the wild strawberries that provide a sweet little snack during morning bird walks. We look forward to seeing what the next week brings as we prepare for the annual census that will give us an estimated number of common and Arctic tern nests in the colony this year. It will be interesting to see how the numbers compare to years past.

Happy birding!

Emma

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Hello from Metinic!

My name is Sequoia, I am one of the two technicians on Metinic Island this summer. I am currently going into my third year at the University of Maine, majoring in wildlife ecology. 

I grew up in a small town in upstate New York, named Moravia. I am an avid outdoors person. I enjoy birding, hunting, hiking, cross country skiing, horseback riding and herping.

While I might not be a “bird person” I wanted to spend this summer learning more about birds so that I can apply the knowledge in the future. Also who wouldn’t want to spend the summer living on such a beautiful island!

My name is Emma and I am the other technician here on Metinic Island. I am a senior at the University of Rhode Island, finishing up my bachelor’s degree in wildlife and conservation biology. Sequoia and I share similar interests, including hiking and working with horses. I enjoy birding along the coast of Rhode Island, especially when there are shorebirds and seaducks involved.

I am thrilled to be spending the summer in such a special place. One of the highlights for me so far was seeing all of the warblers as they passed through during migration. The species diversity on Metinic keeps us on our toes and we never know what we will see next!

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Sequoia on the left and Emma on the right.

We have a bit of catching up to do. We started out the season with a two week quarantine. After flipping a coin, Emma ended up camping in the shed. It wasn’t as bad as it may sound. In fact, one of the best parts about sleeping outside is hearing the storm-petrels at night!

During our first week, we rounded up the 120 resident sheep and moved them away from the tern nesting area. More recently, we kept busy counting the 209 gull nests and 36 common eider nests on the north side of the island. We are continuously documenting all of the amazing bird species here and continue to monitor the common and arctic terns as they get settled and start nesting.

Currently we’ve documented more than 200 tern nests but we’d estimate around 250-300 have been established. Last Sunday we saw the first herring gull chicks hatching and Wednesday we spotted the first ten common eider chicks. 

Though we are already three weeks into the season, we will catch you up as we go. So keep checking in to see what Metinic Island has to offer!

Until next time,

Sequoia & Emma

 

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Two Herring Gull chicks around three days old.

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One of the gorgeous Arctic Terns on Metinic Island.

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A Black Guillemot prouldy proclaiming it’s property.

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The first sighting of Common Eider ducklings this season! The adults stay close to the ducklings to protect them from predators.

 

 

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Greetings from Ship Island!

Bobby Brittingham here! As my time is coming to a close on Ship Island, I wanted a chance to post one more educational blog about our work before a farewell blog!

You may or may not have heard about “bird banding” before, it is an extremely common form of essentially tagging and releasing birds. Using specialized pliers, a small metal “C” shaped band is clamped shut around a bird’s tarsus (leg-like the shin bone equivalent to humans).

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BBL size 2 band, with the identification number, these are the bands used on all of the birds on Ship.

The banding database provides a lot of information on each bird, where they have been seen, where they nest, where they migrate, or even if the bird is alive, as long as the bird’s band is seen and read correctly by another researcher. These bands are essential to distinguishing one bird from another to perform other research procedures or to distinguish which bird belongs to which nest. On Ship we had very late nesting, so Collin and I have been banding as many chicks as possible with our limited time so that these birds can be identified on where they go over the next year.

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Collin banding with specialized pliers, one of Collin’s first banded birds!

Bands vary in size and number of letters based on the size, type of band, and/or species of the bird. For the common terns on Ship Island, a single size 2 “BBL” band is placed around their right leg; these bands each have a unique 9 digit number.  These bands are then entered in an online database through the United States Geological Survey (USGS), and the “status” of a bird can be updated by individuals all over the world. For example, a tern was banded on Petit Manan this summer, and it has already been spotted by another researcher in Venezuela all the way in South America!

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The chicks do not mind the bands as long as they’re put on correctly. When they are put on right, they even look stylish!

For me personally, it is the most fun protocol we perform out here, nothing beats the feeling of getting to meet hundreds of chicks that I have the privilege to watch over every day on this island. Not only that, but it is crucial for research purposes. With the late nesting that occurred this year on Ship, it will be interesting to see where these birds could have possibly gone earlier this year by resightings of the chicks that we band this summer. Be on the lookout for one more blog from the Ship Island crew later this week!

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Hello everyone, this is Bobby writing to you from Ship Island with some breaking news.

The bird word must have gone around, because as of Thursday, July 11th, 321 nests have been found and marked with more being discovered every day! The chaos on the tern nesting beach area is beginning; the eggs laid in late June have begun to hatch this week. Soon our island will be filled with extremely adorable fuzzy chicks who love to run and hide in whatever grass or shelter they can find!

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One of the first chicks on Ship, easily one of the softest objects one could ever hold.

These toddler-like chicks are extremely curious and will wander away pretty far from their nests if given a chance. With them running around all over, it can be difficult to tell how the colony chicks are doing health wise and how many of these chicks are surviving to adulthood. This is answered through a protocol that all of the islands perform known as productivity plots. This may sound like a fancy term, but essentially Colin and I determined a group of nests with eggs that were laid earlier in the season (in our case in late June) that neighbored each other and constructed fencing around them to enclose this area.

 

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Colin (pictured) and I constantly had terns going at our heads to protect their nests while we constructed productivity plots. This one very nicely went feet first to our heads instead of the usual sharp bill first.

This keeps the chicks from our nests of focus from running all over the beach getting into trouble, that way we can determine how many chicks are surviving to adulthood and the size increases of each chick from each nest within our plots. To determine which chick is which, we put stylish metal BBL bands on their right legs that give them a unique identification number for life in a large online database. Colin and I then check each nest in each plot every morning to monitor the eggs and chicks. I am not a parent, but I imagine how I feel when we look for the chicks every morning it is similar to the stressful situation of a parent trying to find their misplaced kids, as Colin and I are really attached to our chicks in the plots. It has been amazing to see the transformation from egg to chick, and soon from chick to fledgling. Watching them grow up has been so special for Colin and I, and we can’t wait to see each chick’s journey continue. More updates coming soon!

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One of the many chicks hatching this weekend, this one hatched within the hour before this photo with a big world to explore!

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(A few of our first of hopefully many eggs on Ship!)

Hi folks!

Bobby from Ship Island here, as the cleverly constructed title suggests, we have eggs here on the island! A total of 13 eggs in 12 nests, which gives us hope that the birds are willing to nest for the breeding season on the island. Whenever Colin or I find a nest with an egg, we turn the egg to stand up, that way when we check the egg later on we can tell if it has been incubated (the egg falls back on its side from the tern sitting on it) or if it has not (egg is still standing up).  However, the number of terns that have been showing up since the last blog post has not been ideal. We have not seen more than 50 terns at once on the island for the past week and a half, at this time last year for contrast, there were 519 breeding pairs. It has become crunch time as we are using our final method to attract the terns back, creating our own tern colony.

This is done with two simple props, audio of a tern colony through multiple speakers, and using wooden decoys of terns (bird manikins essentially). These both simulate that a real colony is on the island and that it is safe to nest for the breeding season. Although it reminds me of The Truman Show in some ways, this method is the best bet to have the terns stay and nest immediately to allow them to be raising young in time for their migrations later in the summer. To paraphrase Princess Leia from Star Wars, the tern decoys may be our “only hope left”, but Colin and I are waiting confidently for our feathered friends to return. Don’t stop believin’ in Ship Island!

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(Terns and the decoys, can you spot the difference?)

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Good evening everyone!

Nesting is well under way here on Metinic. While all the terns are pairing up, it is possible to see a few that are trying to be the envy of the whole colony. How you might ask? Well they flaunt some forage fish of course!

I enjoy watching as a tern will bring a fish onto the point and move all over the place, showing it off to as many other terns as possible. They really know how to make their neighbors jealous!

Forage fish are the main food source for terns. What are forage fish exactly? Well they are species crucial to the connection of the marine food web. Sometimes referred to as “Wasp-waist” species, these fish connect the abundance of zooplankton and phytoplankton in the ocean to the abundance larger predatory fish. Basically forage fish eat the small stuff (zooplankton and phytoplankton) and then larger fish (and seabirds) eat the forage fish. Without forage fish, there would be a large gap in the marine food web.

Monitoring forage fish species that the terns are bringing to their chicks will be crucial once they hatch. A few years back, there was a low abundance of Atlantic Herring (their favorite food), and instead a large abundance of Butterfish. The only problem was that the tern chicks were not capable of swallowing the Butterfish. Despite the large abundance of fish, sadly many tern chicks starved that year.

In recent years, especially in Maine, forage fish abundance has been a widespread issue. Outside of the seabird world, Atlantic Herring and other forage fish are used by people in various ways. However, the most common use for these fish is as bait, especially for Lobster. Many Lobstermen will tell you that while there are other baits that work, Atlantic Herring works the best as lobster bait. That has created a competition between Lobstermen and the seabirds for herring.

There are several papers that have been posted on the important role that forage fish play in seabird producivity. However, one paper has rung true for many seabird species across the globe. The motto of that paper is “One third for the birds”. Basically, one-third of the maximum prey (forage fish) biomass should be saved for the birds to consume. Increases in human uses of forage fish has made this a complicated situation. If you would like to read the paper for yourself here is the link: https://archimer.ifremer.fr/doc/00056/16770/14307.pdf

With all that being said, fish are key to seabird survival! Therefore we need to monitor which species the terns are bringing back to their chicks. (There is a whole other rabbit hole to go down about how we can use seabirds as indicators for the health of fisheries but I’ll save that for another time).

By the way, I have marked a total of 25 eggs so far, with 6 nests identified as Arctic Terns and 5 as Common Terns (one of which has 2 eggs!). I am hoping to have the rest of the nests marked by species in the next few days.

All the best,

Mary

(Photo below: Common Tern with Hake)

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(Photo below: Common Tern with Hake)

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