Feeds:
Posts
Comments

Archive for the ‘Petit Manan 2016’ Category

Recently on Petit Manan Island we have been conducting chick provisioning studies. The purpose of these observations is to determine what prey species are being fed to tern chicks in order to see how prey composition is related to tern chick survival rates. We also record the time of the feedings, which chick is being fed, and the size of each prey item. Over the last decade the fish diversity on Petit Manan has increased. Although it allows us to see new and exciting fish species, it is not a positive sign for the terns. Increased feedings of invertebrate species such as moths, dragonflies, and other insects are also not great signs. Invertebrates and some fish are not as nutrient rich as herring and similar fish species, making them less beneficial for tern chicks. In 2006, common tern feedings consisted of 95% herring. Data from more recent years show that herring has dropped to 25% in 2010 and 34% in 2013 for common terns. Other fish species, such as hake and sandlance, have increased in feeding frequency. Although we do observe feedings of herring, hake, and sandlance, a large proportion of the feedings have consisted of tiny invertebrates and low quality fish species. Throughout the summer we have seen a total of 14 fish species, two aquatic marine invertebrate species, and at least 2 terrestrial invertebrate species being fed to chicks.

Herring and Hake.png

Herring and Hake, respectively

Species like butterfish, lumpfish and three-spined stickleback are not high quality prey items because often tern chicks are unable to swallow the fish. Butterfish are disc-shaped, and often they are too wide for chicks to swallow. Lumpfish are a rough, round fish species that chicks can only eat when the fish are very small. Sticklebacks, as their name implies, have spines on their back that catch in the chicks’ throat when being swallowed.  We often find them uneaten near nest bowls.

Generator Provisioning.jpg

View from Chick Provisioning Blind

Some of the factors that are believed to be causing these changes in fish composition are ocean warming and overfishing. Over the last two years ocean warming has been affecting seabird populations on both the Atlantic and the Pacific Ocean. Seabirds are indicators of marine ecosystem health. Tern breeding pairs have been decreasing on Petit Manan Island for at least the past seven years, and this season marked the first time the total count of tern nests dropped below 1,000. As recently as 2009 Petit Manan was home to 2,500 pairs of terns. This could be indicating that the food availability in the Gulf of Maine is failing, and the terns are not able to find enough prey to be able to reproduce after their migration. To get a sense of what prey species are available to seabirds, we can use our provisioning data as a sample of the prey availability in the waters around Petit Manan Island. Also we can look at provisioning data to see how the rapid warming of water in the Gulf of Maine is affecting prey populations; in particular the herring population.

Using data from all of Maine Coastal Islands NWR and Project Puffin islands, we can learn what is happening in the Gulf of Maine system. This data will assist in monitoring the effects of a warming Gulf of Maine on the marine food web and what this means for the future of our seabirds and fisheries in Maine.

Stickle-back and Butterfish.png

Butterfish and Three-Spined Stickleback, respectively

I have really enjoyed doing these studies because it is exciting to watch the chicks’ daily activities and often the time goes by quickly. For our provisioning studies, each person has a blind that they spend time making observations from every other day. Returning to this specific area every other day is a great way to allow us to see the progress of the chicks and allows us to get to know each chick’s habits. These studies also allow us to see many different fish species as the terns bring them to feed their chicks. This is another great part of the job because it helps us work on our fish identification skills.

-Jimmy and Jill

Advertisements

Read Full Post »

Petit Manan Island is in peak hatching season! The small, delicately speckled brown tern eggs are disappearing and being replaced by similarly patterned fluffy chicks. The oblong, white-brown spotted black guillemot eggs are opening up to reveal all-black downy chicks. Where once we were seeing large, gleaming white puffin eggs, now chicks with long grey down and white bellies are hiding quietly in their burrows. We even have found one razorbill chick (see photo below)! The only seabird still solely in the incubation stage are the Leach’s storm-petrels.

received_1208456342518222.jpeg

One question that I often get asked is, why do some seabirds only ever hatch one chick (think puffins, razorbills, storm-petrels), while others can rear multiple chicks (terns, guillemots, etc)?

In general, seabirds have small clutch sizes compared to birds of other groups like most waterfowl, game birds, and some perching birds. This is because seabirds, unlike the groups mentioned previously, tend to have long life spans. This means it is not quite as critical for seabirds to have a successful nesting season their first breeding season or every year of their life in order to replace themselves in the population. Other bird species may only get one chance to successfully reproduce if annual adult survival is low due to high depredation of adults and/or other factors.

IMG_3440

But why lay only one egg instead of two or even three? There are multiple factors that influence seabird clutch size, and still many questions to be answered. Chick rearing is very energetically demanding for the parents, from egg formation to providing enough food for growing chicks. Right from when birds arrive on the breeding grounds, food availability is critical. After long migrations or rough winters, seabirds need to be able to find enough resources near their breeding colony to allow them to be in proper condition for breeding. Limited food resources during this period of time can cause birds to lay smaller clutch sizes, or even not nest at all.

IMG_4038.JPG

This still does not answer our question why puffins and other species only lay one egg, in both good and bad food years. For species with one egg clutches, it is more beneficial for the long-term survival and breeding success of the adults to raise only one chick at a time. Raising two chicks would probably not be impossible during good food years, but the energetic costs on the parents might make this not worthwhile in the long run. So puffins, razorbills, and many other seabirds prefer to take things slow, laying only one egg per season.

Currently, we have found 17 black guillemot chicks, 15 Atlantic puffin chicks, one razorbill chick, and a few hundred tern chicks!

-Jill

IMG_3921

 

Read Full Post »

Petit Manan Island is well known for its seabird inhabitants, most notably our Atlantic Puffins and Arctic Terns. However, a total of eight species of marine birds return yearly to nest on Petit Manan Island. Most of these birds have conspicuous nests, such as the terns and Laughing Gulls which lay their eggs on the ground’s surface. The Alcids, such as Puffins, Black Guillemots, and Razorbills, lay their eggs in burrows or rock crevices, but the adults are still easily observed on the rocks and surrounding waters. But Leach’s Storm-Petrels, the smallest seabird denizen of Petit Manan, are a little bit trickier to detect.

G0514408.JPG

Jimmy holding an adult Leach’s Storm Petrel that was grubbed from a nearby burrow

Leach’s Storm-Petrels differ from the other seabirds on PMI in a variety of ways. Taxonomically, they are the only species representing a group of seabirds called the Tubenoses to be found on PMI. Also, they are nocturnal and nest in often long, twisting sod burrows.  The burrow entrances are smaller than the size of a fist, and tucked underneath rotting logs, debris and rocks. These life history traits make observing storm-petrels quite the challenge, and prevent accurate estimations of breeding pairs on nesting islands.

This summer we have been testing a new methodology to s
urvey for active storm-petrel burrows. Instead of just reaching as far into each burrow to feel for birds and eggs, we have been playing a recording of storm-petrel vocalizations outside of each potential burrow entrance. The results have been extremely exciting! The birds have been responding with their strange, goblin-giggling call from deep within their burrows. But more importantly, this method has allowed us to find more birds than just by feeling in the burrows. In fact, 63% of the storm-petrels we located only because we heard them – their burrows did not allow us to reach them. Overall, 93% of the adults we located using both methods responded to playback. Hopefully this monitoring technique will provide new insights into Leach’s Storm Petrels nesting on Maine coastal islands!

-Jill

Read Full Post »

As our fifth week comes to an end on PMI, the island is looking more and more like a seabird colony. More Arctic and Common Terns appear every day, and so do their nests. Last week our first Atlantic Puffin, Razorbill and Black Guillemot eggs were found!

G0152078.JPG

Our first Black Guillemot eggs in a rather cavernous rock crevice

 

But this week I’d like to talk about something that is more ever present than the seabirds themselves- marine debris. It’s found all over Petit Manan- some so old that the ground has reclaimed it and the vegetation grows through it. It finds itself lodged between rocks impossible to retrieve, and even ends up in the burrows of the birds we are trying to protect. Although the islands on Maine Coastal Islands NWR are closed to the public during breeding season, trash still lines the shores as a constant reminder of our every day impact.

IMG_3135.JPG

Buoys are a common item to wash ashore on Petit Manan, as well as plastic water bottles, chewing tobacco tins, rope, and bleach jugs. Some of this seems common to local boaters, but the majority of marine debris actually comes far inland and makes its way down through rivers.

 

In the first three weeks on Petit Manan, my co-workers and I collected 840 gallons of trash from the shore. This in addition to the 10 tons of marine debris that refuge boat operator, Jim Fortier, and local Maine volunteers remove annually from Petit Manan Point. Some of our most frequent items include disposable plastic water bottles and other single-use plastic bottles. One afternoon I counted to see just how many water bottles we were picking up, and it averaged out to two water bottles every minute. And they just keep coming ashore.

This isn’t just an aesthetic problem. Marine plastics are a growing problem, especially for our seabirds. Plastics don’t biodegrade or decompose into new material, but they do break down. They continue to break down until they become so small that you cannot see them anymore, these are called micro-plastics. These tiny plastics end up being eaten by seabirds, either because their food already has micro-plastics in it, or because of their feeding strategy like those who skim the surface of the water.

Last year the Oceans and Atmosphere Business Unit of Australia released a study warning that by 2020 99% of seabird species will have been found to consume plastics, and of those species 95% of the individual in each species will have consumed plastics. This news spells disaster for seabird species. Consumption of larger plastic items can lead to obstruction of the bird’s digestion system and death, while eating smaller plastics takes up space in the birds’ stomachs reducing their food intake and leads to decreased health conditions and starvation. This has also been shown to reduce the survival of fledgling and juvenile seabirds.

2311497027_e6df05aae4_o (1).jpg

This image shows all of the marine plastics that were extracted from a single Albatross upon its death. Image courtesy of Tim Zim

So marine debris is a real problem, and if nothing is done it is projected to only get worse. In the 11 years from 2015 to 2026 we are expected to create as much plastic, as all the plastic that has been produced since its creation. Fixing this is not just a matter of watching your trash on beach trips, but to reconsider what you buy and how you dispose of your waste. The majority of marine debris comes from trash that is transported from far inland areas by rivers.

So my challenge to all you seabird lovers out there is to make a positive change in your life. Take the time to clean up and collect recyclables in an area, because you never know if that trash will make it to the ocean. Use your consumer power and switch from disposable water bottles to a reusable one – by not supporting goods sold in plastic containers you are lessening the demand for those goods in the future.  Practice the waste management hierarchy- reduce, reuse, and recycle before ever sending something to the landfill.

Thanks for all your help in protecting in the seabirds we love!

For more information check out these links!

Till next time!

-Morgan

Read Full Post »

This week Petit Manan welcomes the remainder of our crew- Shelby and Jimmy! And with them they brought nesting terns and beautiful weather!

G0061854.JPG

The view from the top of Petit Manan Light. We keep track of Alcid populations by counting them from the top of the Light twice a day!

As our second week on Petit Manan comes to a close, we have given up our reign of the island to the birds. No longer can we go to the outhouse in the middle of the night without hearing the territorial “ka-ka-ka” of Common Terns before they swoop towards our heads. Where once we could walk freely there are now hidden nests and incubating mothers that we must be careful not to disturb. And we couldn’t be more excited!

image.jpeg

One of four Common Eider nests we have found this week. Many more Eiders nest on neighboring Green Island.

image (3).jpeg

While searching for red-backed salamanders, I found this year’s first Savannah Sparrow’s nest hiding under a rotting log!

image (1).jpeg

And finally the one we’ve all been waiting for… the first tern egg of the season! Since then we have found three more nests, but without the safety in numbers of the whole colony nesting, these terns may have abandoned their egg so not to be targeted by Peregrine Falcons.

We hope to have another Egg-cellent week, as next we begin checking rock crevices and artificial burrows for Atlantic Puffin, Razorbill, and Black Guillemot eggs!

Until next time here is a bit of wisdom, “I value my garden more for being full of blackbirds than of cherries, and very frankly give them fruit for their songs.” -Joseph Addison

Best,

Morgan

P5250008.JPG

Petit Manan Seabird Researchers 2016 – Shelby, Jimmy, Jill, & Morgan

Read Full Post »

IMG_3126.JPG

Hey folks! Jill and Morgan here! It’s been a surprisingly beautiful first week on Petit Manan Island; let’s hope it’s a sign for the whole season! The island has been lively thus far with approximately 200 prospecting Common and Arctic Terns, but we’re expecting many more to come! Although PMI isn’t the largest of islands, it still receives a good deal of visitors, especially early in the season when birds are migrating North – we’ve seen 61 species thus far! Not all our guests have been of the bird variety though; we also stumbled upon a juvenile Grey Seal on our rocky shores earlier in the week!

IMG_3032.JPG

Downy Woodpecker sighting!

The start of the season means preparing the island for all the work to be done in the months ahead. This means setting up observation blinds, for band resighting and future monitoring of foraging habits and chick health, as well as collecting marine debris, building burrows for Black Guillemots and Atlantic Puffins, and marking potential Leach’s Storm-petrel burrows. Daily Alcid counts from the top of the Petit Manan Light have also begun. On a windy day it can get rather cold up there, especially for Jill, who hasn’t quite gotten used to the Downeast summer having just returned from a seabird job in the Galapagos!

IMG_3183.JPG

Can you spot the Leach’s Storm Petrel burrow? We’ve been searching the island for these small holes in the ground this past we week, and we have found 170 potential burrows!

As we prepare ourselves for the research season ahead, the birds are doing the same. The puffins and guillemots are seeking out rock crevices and other sufficient and creative hiding spots for their burrows. The male terns are attracting their mates with a Sandlance dowry. The Common Eiders are seeking out areas of high vegetation to form their nests. And the Peregrine Falcons, Merlins, and gulls lurk about hoping to catch a bite to eat with all these new dining options in town.

IMG_3046.JPG

The Atlantic Puffins have already begun choosing burrows!

Till next time, here’s a joke to hold you over – Why did the Puffin have a stomach ache? Because it had Alcid Reflux!

Best,

Morgan & Jill

Read Full Post »