Migrations and change

By Beth Sullivan

There is something about March that always makes me think of change. Looking back over all the years of writing this blog, there always seems to be one dedicated to this topic in March. Of course it is the transition time between seasons, and for many of us, it is a very welcome transition in both temperature and light.

Swallows stage magnificent migrations in the fall.

It is a time of migration

Migration is defined as passing periodically from one region or climate to another. It is also defined as shifting: as from one system or mode to another. We think of the great migrations of large mammals on the plains of Africa. Locally, migration can be a bit more subtle, less earth shaking. In the fall, in particular, the movements can be quite large and impressive, as birds flock and prepare to go south. We have witnessed the magical formations of swallow species as they come to roost at night, in preparation for migration south. School children learn early about the migration of the Monarch butterflies from their northern birth places to the forest groves in Mexico.

The return migration, coming home here, or leaving here for more northern lands, is generally more gradual. There have been reports of large flocks of songbirds making their way north already, in masses so large they show up on radar. Scientists have said it is weeks early. By the time they arrive here, their numbers have scattered, and they are less impressive in their presence. We have to hope that their return here, possibly too early, will coincide properly with emergence of enough insects to fuel them.

These are annual, seasonal migrations. But there are other, more subtle ones. Only a half century ago, there were no red bellied woodpeckers in Connecticut. They were southern species that are now common at our feeders. Other familiar birds, like titmice and cardinals have moved slowly north over the last centuries to set up year round residence. Now they are our familiar favorites. This didn’t happen in one season, or one year, but very slowly as these species moved north where they found adequate food and habitat. In some cases they created a new niche for themselves. In others, they shared resources and even competed with those species that were here before them. The southern birds were not invasive; they were, technically native, just on the move, expanding their range.

But here’s a new one, one that you may not have thought about: plant migration, particularly trees. Obviously trees can’t get up and move when the weather changes; they don’t rely on seasonal food sources, and they need to tolerate and even adapt to sometimes extreme changes. If they can’t adapt, they will die. With the climate changing - warmer overall, less snow cover, periods of heavy rain yet drought in summer, as well as severe weather events the tree species are challenged to adapt quickly. In addition, invasive insects and new diseases are attacking our native tree species with frightening strength and frequency. Warmer winters have allowed these diseases and pests to survive. Chestnuts were among the first to go, over a century ago; then the elms. Beech trees are stricken by bark blight diseases. Birch trees have cankers. Our hemlocks are doomed by the woolly adelgid. Ash trees are being destroyed by the emerald ash borer. White pines are not surviving to maturity due to disease, insects, and the heavy wind events destroying and toppling them. Our mighty oaks cannot tolerate the years of defoliation by caterpillars, combined with summer drought and saturated soils smothering the roots during wet winters.

Beech trees are doomed by a bark infection called blight.

The great mammal migrations in Africa are famous.  Photograph by Binti Ackley.

National Weather Service radar picks up a migrating flock of songbirds over Florida. (National Weather Service picture)

Fifty years ago there were no red-bellied woodpeckers in Connecticut.

Assisted migration

When openings in the forest are created, either man made or nature made, what fills back in are often the same species from seeds that have been in the soil. They will be faced by the same challenges.

Scientists studying this issue are beginning to think of a concept called assisted migration. Trees can’t move far or fast on their own, like birds can. It takes centuries for plant species to expand their range northward as conditions change. One approach is the idea of assisting nature, by bringing north tree species that are native to areas just south of here, species that are adapted to conditions that we are now experiencing. There are oaks and pines that can occupy the same niches as our historically native ones do. Wildlife can make use of these more similar native species, much better than they can non-native species from other countries. Southern natives are less likely to ever become invasive.

We have a number of tree species that are present now, at the northern limit of their range, such as the tulip tree and tupelo (Black gum), and as climate warms they will be tolerant and spread. But we can make it happen faster by using such species to fill in openings and clearing.

As we begin our planning for the restoration of the forest at the Hoffman Preserve, we are beginning to research mid-Atlantic species that may grow and adapt and help create a forest that will last through the next century of change. It is very interesting and hopeful. Stay tuned.

Our mighty oaks and hemlocks are stressed and will not survive the warming climate.

The tulip poplar tree is present in southeast Connecticut but is also tolerant of more southern conditions.

Photograph by Beth Sullivan, unless otherwise noted.

Purple Martin Season 2018

by Beth Sullivan

It has begun! Those of you who have followed this blog for several years, know of my commitment to (some say obsession with) my Purple Martins on Knox Preserve. You can catch up on recent history in earlier posts, here and here.

There are dedicated websites to document the Martins’ movement north, and it is always amazing the consistency that governs these migrations. For all of us, spring seemed to have gotten off to a very slow start, but by mid-April we were getting reports that the Martin scouts had been spotted in the area. We got up the first gourd system at Knox on April 21 and were immediately rewarded with several birds all checking out the best real estate. Established pairs tend to return to the same colonies each year, and the young, from previous years, get second dibs or move on to expanded colonies. The second set of gourds went up the following week. It was encouraging because at that point in time, it appeared that spring might actually stick around: there were flies, butterflies and other insects present in the air over the fields.

After being washed, marked, and stored for the winter the gourds were ready to hang in mid-April.

Adult males get first choice for nests

Purple Martins move in

I have been keeping watch for the last couple of weeks, and while the weather recently has not been optimal for flying insects or for anything flying, the birds are returning and are beginning to put their claims on various gourds. If you sit on the bench on the hill at Knox, and have a good pair of binoculars, you can actually follow their antics and aerial acrobatics. You will also see that there are House Sparrows also trying to get established in the gourds as well. Part of my job as landlord is to do periodic housekeeping when I will lower the gourds and remove the nests of the Sparrows. It is very easy to tell them apart: Martin nests are lovely and neat and lined with green leaves, prior to egg laying. House Sparrows fill up the entire gourd with a tangled mess of straw and debris which needs to be pulled out. In persistent cases we will close the hole up to keep them out, but we always fear they will be so aggressive they will fight and even kill a Martin, to displace it. Please: Do NOT encourage the proliferation of House Sparrows in your bird houses. As they are invasive and non-native; they are not protected and we are all encouraged to remove them.

House Sparrows tend to jam tons of straw into a cavity and their eggs are speckled.

Purple Martin nests less crowded and neater with pure white eggs.

New apartment house for Purple Martins

We do have a wonderful new addition this year. Through a couple of fortuitous connections between Purple Martin landlords, we were offered a complete Martin house set up from Menunkatuck Audubon. This Audubon group supports a number of great projects farther down the CT coast. Most notably, they support and monitor the Martin houses at Hammonasset State Park. They also monitor several Osprey nests, including one with a camera. You can find it here. We connected with landlords Lorrie and Terry Shaw and met them at Hammonasset one cold day in early April. They were in the process of updating their Martin housing so all would be the same style and function, making it easier for their volunteers to monitor. They had not one, but two, beautiful complete set ups for us to bring back to Avalonia territory. These are the more well-known style of apartment house nests but with all the high quality updates of easy winch and pulley system and easy to clean nest trays. We put up one at the Wequetequock Cove Preserve on Palmer Neck Road on the way to Barn Island. It is an ideal site, open fields yet near people and water, but because there are no other colonies in the area, it will be more of a challenge to attract the birds right away. We added a couple of decoy birds to attract attention.

It is arrival time right now. The younger birds will be a bit later and will be looking for new colonies. Our Knox preserve colony is active but we have not yet seen Martins at our new site, just House Sparrows. They will not be allowed to occupy this new abode. If you drive by, look for the house in the south field. There is room to pull over and spend a few minutes looking. The fields have been home to Bobolinks in the past. The wet areas have had Glossy Ibis and shorebirds recently and many Red Winged Blackbirds call from the grasses where they will nest. This is a known hot spot for birds in all seasons. Let’s hope the Martins will find the new home inviting and we can add to the species list.

We haven’t yet decided on the best place for house number two. We’ll see how this one does. Many thanks to the Menunkatuck Audubon Society for their amazing gift to us and the Purple Martins.

The new house is up on Wequetequock Cove Preserve.

Two sets of gourdes are up at Knox Preserve and already have residents.

Hopefully ours will full up soon like this one at Hammonassett Beach State Park. Photograph by Terry Shaw.

Photographs by Beth Sullivan unless otherwise indicated.

The Horseshoe crab, a living fossil

By Rick Newton

On the list of the Nature Conservancy’s top migrations is that of the horseshoe crab (Limulus polyphemus). It is truly a wonder to experience. Horseshoe crabs are called a living fossil; they have been around for over 350 million years virtually unchanged. It is not really a crab as it is associated more closely with spiders and scorpions. Worldwide there are four species of horseshoe crabs but only one in the United States on the east coast.

In late spring and early summer, mainly around the times of full and new moons and on the hide tide cycle, horseshoe crabs migrate from their wintering grounds to local beaches to lay their eggs. The female crab, usually with a male crab grasping on to the female’s shell with a pair of modified legs resembling boxing gloves, buries herself into the sand laying a cluster of around 4,000 eggs. Over several nights the female may lay as many as 100,000 eggs. About a month later, the eggs will hatch, and tiny horseshoe crabs will spend the first few years of life on tidal flats and marshes.

Horseshoe crabs molt many times before reaching maturity. 

Because horseshoe crabs have a hard shell they must molt to grow. They will molt around six times in the first year and up to eighteen times before reaching sexual maturity. Once the crabs reach sexual maturity, which takes about nine or ten years, the molting stops. When the male crab completes its final molt, the front claws take the shape of boxing gloves that he uses to grab on to the female for spawning. A horseshoe crab's lifespan is believed to be 20 – 30 years.

Horseshoe crab bodies are composed of three parts: prosoma (head), opisthosoma (central area), and telson (tail). Horseshoe crabs cannot hurt you. Many people think the tail is some kind of stinger, but it is mainly for allowing crabs to flip themselves over should they get turned upside down. Horseshoe crabs have ten eyes, and much of the research on human vision has been accomplished using horseshoe crabs. Horseshoe crabs have book gills to get oxygen from the water and can live on land for up to four days if they get stranded. Their food consists of razor clams, soft-shelled clams, and marine worms.

Horseshoe crabs are important for a few reasons. First, shorebirds migrate from South America to the Artic. Most need to stop and rest and feed on their travels north to their summer breeding grounds. Their migration coincides with horseshoe crab spawning. Eggs that are exposed to air by wave or boat wake action or by the digging action of other crabs, quickly dry out and won’t hatch. But these eggs are the primary food source for the migrating birds allowing them to double their body weight in less than two weeks.

Not just a fossil

Second, horseshoe crab blood plays a vital role in human medicine. Their copper-based blood, which turns blue when exposed to oxygen, contains blood cells called amoebocytes. A testing reagent called LimulusAmoebocyte Lysate (LAL) is derived from the amoebocytes of the horseshoe crab. The LAL is used to test the sterility of vaccines, drugs, and other medical devices. However, recent biomedical developments have shown that a synthetic compound may be an alternative to using horseshoe crab blood, thus saving hundreds of thousands of crabs from being bled. You can learn more here.

Horseshoe crabs have few natural predators except for seagulls or raccoons that may feed on an overturned crab. Major threats are from harvesters (who sell crabs as bait for conch, whelk and eel), human disturbance, and loss of habitat due to beach development or shoreline modifications as communities harden the shoreline to deal with rising sea levels.

Avalonia’s Sandy Point Nature Preserve is one of the primary spawning areas for horseshoe crabs with hundreds of crabs coming to the beach on peak cycles. Volunteers from Avalonia, Mystic Aquarium, and others support Project Limulus (Sacred Heart University & USFWS) in southeastern Connecticut. These volunteers are citizen scientists counting, measuring, and tagging horseshoe crabs during the early spring and summer.

Be a citizen scientist

Anyone can help by just walking the beaches and looking for tagged crabs. If you see a tag on a dead crab, remove the tag and report the tag number, date, time and location to the number on the tag, or provide this information via the internet at: http://www.fws.gov/crabtag/ If you see a tag on a live crab, just write down the tag number and report it as above, leaving the tag on the crab. If you see any crab upside down, just flip it over by grasping it by the side of the shell (not the tail).

If you see a flipped Horseshoe crab on the beach.

Give it a hand and turn it over by its shell.

Tagged horseshoe crabs – Groton / Stonington area – 2009 to 2017

Note: some of the decline in tagged crabs is due to budget reductions to the USFWS with fewer tags being distributed. In general, however, volunteers are seeing fewer crabs each year.

You can read more about Horseshoe crabs in   The Underwater Secrets of Horseshoe Crabs, here.

photographs by Rick Newton

The Northward movement

By Beth Sullivan

Migrate: To pass periodically from one region or climate to another, as certain birds, fishes or animals.

March is a month of migration. In many places the process began much earlier and will not stop until everyone or everything is where it’s supposed to be, to breed and raise young, and then it begins all over in reverse.

Now that the day lengths are increasing, and daylight hours are nearly equal to night hours, many creatures are being inspired to make their migration, usually in a northward direction, back “home” here, to where they belong, in our opinion.

In the month of March, I usually begin my list of firsts: things like Peepers and Wood frogs are important firsts. Those are checked off. The first Painted turtles out on a log have been spotted. But they never ventured far. They just stayed down and under all winter. They emerged recently to greet the warmth, but will dig back underground in the face of the cold that is surely coming in this fickle month.

The first Purple Martins have arrived in places like Florida and Texas, but they will not reach here until April. So I don’t get my hopes up for them for a while. You will certainly be getting reports as soon as ours arrive.

Purple Martins have already begun housekeeping in Florida. Photograph by Dennis Main.

March migrants

The migrants of March are the Osprey, the Eastern Phoebe and the Tree Swallows, that I eagerly await. For sure there are many more, but these have always been my true indicators of spring. All three of these arrive within a week, more or less, around the Vernal Equinox- the first day of spring. So much, though, depends on the weather that either assists them or keeps them grounded. If we get a nice southerly flow, they will all catch the wind and arrive earlier. If we continue to be hit with Nor’easter type storms, they will hunker down where they are and wait.

Interesting to note though, even as we eagerly anticipate the first sightings of these new arrivals, we sometimes overlook those migrants who slip away quietly from our area, to return farther north to their own breeding grounds. Sometimes it’s hard to remember the last Hooded Merganser I saw on a cove, or, come later into March and April, when I no longer hear the Juncos twittering in the bushes.

 The bird I really wait for is the osprey, sometimes showing up for St. Patrick's Day.

This Phoebe in Florida, is a real sign of spring in New England, but won't arrive until it warms up and are there are insects to eat. Photograph by Dennis Main.

Tree Swallows will arrive in a few weeks. Photograph by Rick Newton.

Sometimes it's hard to remember when the last Hooded Merganser took off from our icy coves to return north.

Another kind of migrant

There is another interesting group of migrants: people, know as snow-birds - those who leave the colder climates, not necessarily to breed and nest of course, but to escape the cold and enjoy the climate farther south.

What is also pretty funny to think about, is that many of the birds that leave here in the winter, end up in the same area as our snow-bird friends. Those Osprey, Phoebes and Tree Swallows, as well as Egrets, Herons and many Warblers are all down south with our friends and likely will return around the same time.

Also, thanks to population shifts, many southern birds have expanded their range north, so birds such as the Tufted Titmouse, Carolina Wren and Red Bellied Woodpecker have only recently, relatively speaking, become established here in Connecticut.

We may never see Wood Storks or White Ibis here in Connecticut, but that’s OK. I am always most eager to see that first Osprey of March and welcome them back to their nests here. And I will look forward to seeing friends return as well.

The Red Bellied Woodpecker only arrived in this area from farther south within the last four decades. Photograph by Dennis Main.

Some birds like these White Ibis, will probably never expand their range this far north, but who knows what climate change will bring. Photograph by Alan Brush.

Photographs by Beth Sullivan unless otherwise indicated.

Coming and Going: Transitions

By Beth Sullivan

A couple of weeks ago, my hummingbirds left. Right on time- on the first or second of October. There are still flowers full of nectar, we haven’t had a frost yet, but the time and light was right and their migration began. For a few days the Downy Woodpeckers and curious Chickadees used the nectar feeder. Bird watchers in my area have noted this behavior over the last years and we wonder if it is a local learned behavior. These birds will stick around, but the hummingbird feeder has been brought in and cleaned for the winter.

I am always amazed at migrations. As a kid ( okay...and as an adult) I watched the timeless journeys of the large mammals in Africa, always in awe of the volume, mass and energy of the large herds. But I am even more in awe of the smaller creatures and their abilities.

As we lose our nectar-sippers, the insect-eaters are not far behind. While it is hard for us as lay people to know the difference between one Common Yellow Throat and another, science has been able to inform us that those that were born in our area are moving on, heading south, and those we may encounter now as we walk a wetland thicket are likely from more northern origins.

Goldfinches will be happy with wild seeds and birdfeeder offerings. Photo by Rick Newton.

Hummingbirds have fueled up and left the area.

Shorebirds, like this Yellowlegs, have an extended migration period.

More on the coast

Because we live on the coast, we have greater numbers of migrants. It is also known that most birds, especially the young of the year, migrate along the shore line. It might be a visual cue, maybe there is something atmospheric as well. But as they follow this Atlantic shore line, flying most frequently at night, they “drop out” each morning for their R&R in the coastal thickets and shrub lands. Hiking at places like Barn Island, Bluff Point, and Knox Preserve, or visiting off shore islands like Fishers Island or Block Island is a bird watcher’s heaven. Be on the look out for a great variety of fall warblers, thrushes, vireos, and others making their way south through this month.

Shore birds have mostly finished passing through here. The adult plovers, sandpipers, and other shore bird species leave their nesting areas in the far north well before their own young can fly. They also migrate along the shore line so local beaches are often alive with the small birds, picking through seaweed and resting up. Their young will follow up to a month later, usually following the same route, and often landing on the same beaches in South America as their parents. Bird banding studies have proven this, and now radio telemetry has made it even more accurate.

Flocks are forming

The Swallows are still massing before they roost every night, but that spectacle is nearly over. Our Martins left first, making their own flocks. In more southern areas, their roost flocks are so large that they show up on radar. The same occurs with the mixed flocks of Tree, Barn and Rough Winged Swallows that collect in marshes, most notably at the mouth of the CT River. Each evening they gather and swirl, and then settle to rest and ready themselves for their push southward.

From this, it sounds like we will be birdless shortly. Don’t despair. The sparrow numbers are already increasing in the grass lands. At Dodge Paddock, Knox Preserve, and Fennerswood, the weedy fields are full of chirp notes as they search for seeds. More northern finches will arrive and populate the thickets. It is time to bring out the seed and suet feeders. It is also time to think about Project Feeder Watch here, which gives us all an excuse to get out and look for the birds of Autumn.

The process of bird banding gives us greater insight into migrations. Photo by Rick Newton.

Nightly, thousands of swallow mass in preparation for their migration. 

Soon the Hooded Mergansers will arrive in local coves.

Sparrows are in abundance in local grassy fields.

Photographs by Beth Sullivan unless otherwise indicated.