Avalonia eTrails: July 2013

Thursday, July 25, 2013

Continuing the Mission

Avalonia Land Conservancy’s mission statement reads: “…Preserving natural habitats in southeastern Connecticut by acquiring and protecting lands and by communicating the value of these irreplaceable resources”.

In order to better understand and communicate the value of our resources, Avalonia promotes educational efforts on our preserves. By welcoming students and supporting their projects we benefit from their knowledge and insight as well as make valuable connections to the extended resources they represent.

Here in Stonington we have a widely varied offering of habitats and preserves. Over the last several years we have made some wonderful academic and scientific connections and offered numerous opportunities for study. We have had students as young as preschool, and all the way through college and graduate school, working on projects on Avalonia properties.

In 2011-12 a student from Brown University studied the presence and effects of Sesarma (Marsh Crab) on the Cottrell Preserve. These crabs burrow in the mud along salt marsh edges, consume the grasses that support the edges, and seriously erode the marsh when their populations are large.

Holes used by Sesarma Marsh crabs can cause erosion.

For several years, including 2013, University of Connecticut students have visited several marshes in town, including the Woolworth Preserve and Paffard Marsh this year, to study the birds that make use of the different habitats associated with these areas. Arriving at dawn, the different teams looked for the uncommon Seaside Sparrows and Salt Marsh Sparrows as well as other marsh nesters. Other teams surveyed the areas where the woodlands met the marsh for birds that use these areas.

Yellow Warbler is one of many species that use marsh edges.

On the Peck and Callahan Preserves, the USFWS and DEEP, along with Avalonia volunteers, will begin a long term study of the wildlife that makes use of the newly created shrub and young forest habitats. We will especially be looking for the New England Cottontail and several shrub dependent birds like the Brown Thrasher and Yellow Breasted Chat.

The Knox Preserve has been the focus of many studies over the years. For two decades, Federal Bird Banding has been conducted on the preserve and meticulous records kept of observations and populations and species. This year, with the successful establishment of a Purple Martin colony, the DEEP conducted a special banding operation to add to the data being collected about this species, their migrations, returns and dispersals throughout the area.

Robin being processed prior to banding.

Purple Martins at the Knox Preserve are now part of a migration and dispersal study.

Connecticut College students from the Goodwin Neiring Centerfor Environmental Studies, conducted numerous projects this past year. They included studying the drainage and plant life of the brackish pond there. Another group studied the field restoration effort and introduced native plants; others enhanced the bird housing availability on the property.

Sandy Point, our Island just off Stonington Point, has long been studied. The bird populations are documented frequently during the nesting season with special attention to Piping Plovers, Least terns and American Oystercatchers. Horseshoe crabs are tagged and counted as part of an ongoing study, Project Limulus, conducted by Sacred Heart University. The island is well renowned for its population and nesting habitats for these ancient and valuable animals.

Project Limulus studies the Horseshoe Crabs at Sandy Point.

Dodge Paddock, which has been the subject of efforts by Avalonia and DEEP to improve the habitat by improving drainage and removal of the invasive Phragmites, will also now get its own study group. A doctoral fellow and team from Trinity College will be monitoring the Phragmites removal efforts, and will concentrate on regeneration of native plant diversity in the areas where the Phragmites have been eradicated and the effect the treatment has on the soils in the area.

A new team will study the long term treatment of

Phragmites that have taken over Dodge Paddock.

Every time we encourage a study effort, we benefit from the knowledge they have gained and in turn are better able to steward the lands entrusted to our care.

Written by Beth Sullivan. Photography by Beth Sullivan and Rick Newton.

Learn more about the preserves mentioned here at avalonialandconservancy.org.

Thursday, July 18, 2013

Digging deep to study the Horseshoe Crab

Over the past months, you may have followed discussions about our efforts to count and tag horseshoe crabs on several area beaches and Avalonia’s Sandy Point Island.

On Wednesday, July 17, Avalonia volunteer taggers Binti Ackley and Beth Sullivan were joined by Professors Jennifer Mattei and Mark Beekey, and four students from Sacred Heart University to do further studies of the population on the Island. Thanks to Avalonia member and Pine Point science teacher Jon Mitchell we were transported, gear and all, back and forth, and he joined the group.

The Sacred Heart team has been studying all aspects of Horseshoe Crab biology: life spans, migration routes, mating studies, habitat quality, nesting and hatching studies as well as all stages in between. A great deal of information has been amassed over the last decade and they continue to compile and add to the data base.

On this morning, we arrived at the beach at low tide, giving us the greatest expanse of beach where we expected to find nest depressions, as well as mud flats and small pools where we might find newly hatched juveniles. Horseshoe crab nests are mostly dug during the high tide and at night. This morning there were dozens of depressions along the high tide line indicating nesting activity over the last week. We gently scraped away layers of sand until we uncovered the clusters of eggs. Newly deposited eggs are glistening grey/blue, not much bigger than grains of sand, and are somewhat clumped together.

Horseshoe crab eggs look like small pearls mixed in the sand.

As the eggs mature, they appear to become more beige or peach colored, and the ones that were closest to hatching were nearly translucent and the minute crab could be seen, at times, moving inside the egg. Samples of eggs were taken from dozens of different nests along the shore. They will be evaluated for numerous things. Some will be checked for heavy metals, including lead. This is often found in habitats near where hunting has occurred and the lead shot becomes absorbed into the sand area and into the eggs. They will also evaluate for the caloric content of the eggs to see the quality of the “food supply” inside of the egg, usually measured in the fat content, and may indicate health or viability.

Another interesting aspect of examining the nests was the presence of an entire community of organisms that live within the nest. The organisms are dependent on the eggs, the spawning fluid or milt, the sugar based material that holds the eggs together, and the bacteria that develop within the nest. There were worms, isopods, amphipods and even beetles that spend their life cycle within horse shoe crab nests. Many nests had deep holes poked into them and footprints all around from numerous bird species, notably sandpipers and oystercatchers that probe for the nutritious eggs.

Examining a nest for eggs. Note the bird foot prints surrounding the area.

In the mudflat pools we were shown how to really pick out the newly hatched, juvenile crabs, that were so small they were easily mistaken for tiny bits of gravel. The very smallest were probably hatched within the last weeks.

Newly hatched horseshoe crabs.

We also found juvenile crabs that ranged up to two inches across that were probably the young of last year. These burrow to forage in the mudflats and may be found by their trails in the sand. There were also weighed, measured and categorized.

A one year old juvenile.

Underside of a juvenile.

We also scouted for adult crabs, though they were hard to find because of the time in the moon cycle as well as the tide levels. We did find at least five and they were weighed, measured and photographed, and samples taken from each to assess health and heavy metals in their blood.

This Horseshoe crab was tagged at least three years ago.

Taking samples from an adult horseshoe crab.

Documenting a tagged visitor to Sandy Point.

The scientist team checked soil samples, plant material, other invertebrates, small fishes and snails that share the habitat with the crabs.

It was pretty amazing to explore the web of life and interdependency to be discovered along a special stretch of sandy beach.

We are excited to have a connection with the Sacred Heart team and look forward to sharing their data and learning more about a special inhabitant of our Avalonia Island.

Written and photographed by Beth Sullivan.

Find out more about Project Limulus.

Thursday, July 11, 2013

Update on Purple Martins at Knox Preserve

Back in June, we reported that we had erected a 12 unit SuperGourd System at the Knox Preserve. This was funded by an Audubon IBA ( Important Bird Area) grant.

By April 28, we had our first serious investigators into the new real estate in the area.

By early June, there was a lot of activity around the houses, but it was hard to tell who was serious about nesting. Apparently this is normal behavior for Martins. There was a lot of chasing, swapping, and peeking into multiple cavities. Nest-checks at this time revealed several gourds with extra nest material added-a hopeful sign. The following week we noticed an unusual pattern to the Martins behavior; they were landing in a cherry tree and ripping off leaves and carrying them back to the nests. This is a sign that egg-laying is very imminent. There are theories that some green leaves, especially those of Wild Cherry, have a type of toxin that is released when they wilt and which may act as a deterrent to bird mites which are parasites on young birds. Too many mites, which suck blood from helpless, featherless nestlings, can weaken the young and cause death.

We conducted a nest check on June 16 by lowering the whole system and peeking into each cavity. Eureka! Success-several nests contained eggs, all nestled in among the green leaves!

A clutch of five Purple Martin eggs nestled on
cherry leaves to protect against mites.

Martins lay one egg daily, at dawn, until the clutch is complete. A clutch can be anywhere from three to eight eggs. Five is average. By assessing eggs and clutch size, we estimated that first hatching could be around the last days of June to July 1.

On June 21, we checked again, and each of the four nests had completed clutch sizes of five lovely pale cream white eggs. Another newer nest had green leaves added but no eggs yet.

By June 30^th we were anxious to see what would await us. Hatching! One nest had one baby and still four eggs. Two nests had five small, pink, helpless looking hatchlings, probably only out of eggs within 24 hours. I felt like a first time grandmother! The parent birds keep the nest immaculate. There were no old eggs shells, and the adults remove fecal sacs constantly.

One hatched-four to go.

Full house-five hatchlings.

The following week was the brutal heat wave, baking sun, and high humidity. I feared for the colony, but there was nothing to be done to get them through it.

We gathered our supplies to make a check and also to change out the nest material on July 7^th . It is recommended that “landlords” remove old nest material when the birds are about a week to 10 days old. By this time, infestations of mites can reach serious levels. Research shows greater success in those colonies where the nests are monitored and changed.

I am thrilled to report that we lost no young to the heat and even added a few babies!

Three nests had a total of 11 young, all about 10 days old. One other nest contained five new hatchlings.

A 10 day old clutch, riding out the heat.

Another clutch of newborn hatchlings.

Changing out the nests was a challenge at first. But it all proceeded quickly. The young were removed to a clean basket. Old nest material was removed, and yes...there were mites all over inside, outside, on my arms, everywhere! No, they don’t harm people, but they sure make you feel crawly! We cleaned out the gourds, replaced new pine needle nest material, and I decided to add a few new green cherry leaves. I did notice that the nest that had the fewest leaves had the most mites. The nest that had dozens of leaves had far fewer mites. Maybe there is something to the theory.

When the process was completed, all in about a half hour, we raised the nests, and the adult Martins flew in immediately. Apparently they have no problem readjusting the new material and settling in.

Hatchlings on their first trip out of the nest.

Hatchlings waiting while their nesting materials are changed.

We will plan on doing a Federal Banding of all our nestlings and possibly a DEEP color banding for study purposes. This will occur before the young fledge and are about 10-20 days old.