Ian Stewart

Migration is a fascinating aspect of animal biology. Each spring and fall, millions of birds, mammals and insects fly thousands of miles to get to either their breeding or wintering grounds. Migration can be challenging to follow however, as many of these animals migrate at night and travel quickly. There are several methods scientists use to track migration but a new collaborative method has recently emerged: the Motus system.

The Bucktoe Motus tower

The Motus system is an international network of automated towers which detect any animal fitted with a special small tag within a 15km range (‘Motus’ = Latin for ‘movement’). Since each tag emits a unique signal it is possible to track the movement of individual animals as they pass by one of more towers. The great majority of animals fitted with tags are birds but tags have also been placed on bats and large insects like dragonflies or even butterflies! The Motus network allows scientists to collect data on tagged animals to help them find out how variables like weather and the animal’s age, sex, and physical condition affect the timing and speed of their movements. It also aids conservation efforts by identifying key areas where animals stop to feed and rest during migration which can then be protected.

There are over 200 towers spread across the world, most of which are in North America (see the map on the Motus homepage www.motus.org). In the summer of 2017 a team of dedicated field biologists erected a line of towers all the way across Pennsylvania. The towers are so close together that their detection ranges overlap, meaning that they would pick up every tagged animal that migrates north or south anywhere in the entire state!

Distribution of Motus towers across PA and DE

Thanks to generous funding from the Starrett Foundation and the Pennsylvania Department of Conservation and Natural Resources via the Willistown Conservation Trust, a Motus tower was erected at Bucktoe Creek Preserve near Kennett Square in August 2017 as part of this line and has been recording 24/7 ever since! In the fall of 2017 it detected 7 thrushes, 3 warblers, a woodcock and a bat, all presumably heading south for the winter. In the spring of 2018 it detected a thrush and 4 shorebirds, all likely heading north to breed.

Another remarkable feature of the Motus system is that much of the data is open-access and can be viewed by anyone with the Internet. To see what animals are being detected follow these 4 simple steps.

1. Visit the homepage at www.motus.org then scroll down to see a map of the world with a yellow dot representing each tower.

2. Zoom in to find the tower you’re interested in (e.g. Bucktoe Creek) and click the dot. A box will then open telling you the name of the tower and its location plus the contact details of the organization overseeing it. The bottom row gives the number of tags detected by that tower (if there have been any) with ‘table/timeline’ in parentheses next to it.

3. Click on ‘table’ and a new page will open with several columns including the date each tag was detected plus the ID# of that tag (in blue text) and the species it was placed on.

4. Click on the ID# to reveal the date and place where the animal was tagged, and then if you want to explore further, either click on ‘table’ in the bottom row to see a list of towers at which that bird was detected, or ‘timeline’ to see what time the animal passed by the tower and how long it stayed. My own favorite is to click on ‘map’ to show the route the animal took!

Every year more Motus towers are erected throughout North America and they are also starting to spread across other continents. The number of tagged animals is also steadily increasing and every time one is detected it adds to our understanding of animal migration. Watch this space for updates from the Bucktoe tower!

Story and Photos by Joe Sebastiani, Ashland Nature Center Manager

What happens on a Delaware Nature Society Eco-trip? This spring’s adventure to Montana and Yellowstone featured lots of Black Bear, Grizzlies, Bison babies, over 150 species of birds, and world-class scenery. Throw in a few overnights in haunted hotels, cute mountain towns, and great food, and you have the recipe for an eco-trip to remember for a lifetime.
Forrest Rowland from Rockjumper Birding Tours led the trip. Forrest leads groups around the world, but lives in Montana. Joe Sebastiani, Ashland Nature Center Manager, accompanied the Delaware Nature Society group to experience one of America’s most wild and beautiful areas.  Many fans of the Ashland Hawk Watch know Forrest as the first Hawk Watcher during our 2007 inaugural season.  Now he is in charge of New World Operations for Rockjumper, and a highly sought-after guide.

Richardson’s Ground Squirrel looks like a pint-sized Prairie Dog. This one is barking at our group!

Our trip started in the short-grass prairie ecosystem around Billings, and focused on finding the birds of the region.  Many prairie species are declining, and some of the rare ones take inside knowledge of where to find them.  Luckily, Forrest lives in the area, and is tuned-in to where pockets of decent prairie habitat remains that supports birds.

Some of the highlights include watching the breeding displays Sprague’s Pipit, McCown’s and Chestnut-collared Longspurs as well as Long-billed Curlews chasing Golden Eagles.  Curlew disdain for eagles is known right away, as they scold and chase the larger eagles, America’s most powerful predatory bird, across the prairie.  Rare prairie nesting species we encountered included Ferruginous Hawk and Baird’s Sparrow.  A few species I thought I would never see in my life.

Chestnut-collared Longspurs fly up in the air and parachute back to the ground on wings held high, impressing feathered and human onlookers.

We were lucky to encounter a Plains Hog-nosed Snake which allowed us some close-up looks.

After the prairies, our group ventured into the foothills of the Rocky Mountains in southwest Montana.  Our base was Livingston, and we enjoyed the town and hotel as much as the adventures.  The Murray Hotel, downtown, allowed us to experience an old, western, authentic establishment, that is famously haunted, especially on the third floor, where my room was!  After returning from an old burned-over woods containing Lewis’s Woodpeckers, and visiting a wonderful bird feeding station with Evening Grosbeaks, Cassin’s Finches, Red Crossbills, and many others, the Murray awaited.  The rooms were well-appointed in Western and Native American decor.  Old photos of folks dressed in long-ago outfits decorated the walls.  I did not have a supernatural experience that night, but others in the group might have been in touch with the spirit world.

We visited two fantastic feeding stations, allowing opportunities to view hard to find species such as the Evening Grosbeak, a large finch.

Forrest Rowland, our Guide, enters the Murray Hotel in Livingston, with its famously haunted 3rd floor, where my room was.

Our group eagerly awaited Yellowstone National Park.  Large mammals abound, not to mention otherworldly hot springs and geothermal features.  Our first stop was Mammoth Hot Springs, which bubbles up boiling water, creating a beautiful cascade of dissolved limestone that reforms when in contact with the air at the surface.  Said to look like an inside-out cave, Mammoth Hot Springs is a beautiful sight, combined with sulphury smells, hot steam, and swirling colors.

Mammoth Hot Springs

We took one of the longest hikes of the trip here, partially to find Dusky Grouse and Williamson’s Sapsucker.  We found the Grouse by listening for its soft, low, cooing calls, produced by pinkish air sacs on the side of the male’s neck.  Forrest heard it, located it, and had us making concentric circles around the bird, without making eye contact with it, until we were right on top of it, taking a seat feet from the bird.  It went about its business, unconcerned by our proximity, so it seemed.

This male Dusky Grouse allowed us to sit practically next to it, as it made low, soft cooing sounds from the air sacs on its throat.

Along the walk, a few of us were looking at a butterfly, trying to identify it, when a brown figure was seen walking up a side trail towards us.  EEEEK!  It was a bear!  We noticed it when it was about 25 feet away, which is rather close.  We quickly stumbled away from it, walking at first, then moved with a little more urgency towards Forrest, who had the can of bear spray.  Hearts were racing, and there might have been a little pushing, but it turned out to be a young male cinnamon-colored Black Bear, only interested in getting a drink at the nearby creek, and eating some flowers.

This mild-mannered cinnamon Black Bear certainly startled a few of us on the trail, as we did not notice it until it was very close to us.

After our Bear encounter, we moved on to some of the large, open valleys in the park to seek other large forms of wildlife.  One way to do this is to stop where other people are on the side of the road looking at something.  One of our first “wildlife jams” on the road was caused by a mother Grizzly Bear and her two cubs tearing apart an elk that she had just killed.  As we watched them feed (300 yards away through the scope), you could see them tearing meat off the carcass…a brutal reminder there are animals here that are one step higher up the food chain than you.

For many of us, it was the herds of Bison that made the show at Yellowstone.  These hump-backed, woolly cow-like creatures plod around grasslands, roll in the dirt, walk down roadways, butt heads, and move along with young calves, right in front of you.  The calves are extremely cute, and allowed us fabulous looks.

In early June during our trip, it was “Cute Calf Season” for the Bison.

During our last few days in the park, continued our search for wildlife.  Sightings included Coyote, White-tailed Deer, Mule Deer, Bighorn Sheep, Mountain Goats, Moose, Pronghorn, and many species of birds including Harlequin Ducks and Barrow’s Goldeneye which inhabit the fast-moving rivers in the park.  One thing we missed by 10 minutes, however, was Gray Wolf.  We gave it a good effort, but didn’t end up seeing them.

Coyote are apparently more difficult to see in Yellowstone that Gray Wolves. We missed the wolves, but had this Coyote walk right past us.

Finally, although it was early June, we couldn’t leave the Rocky Mountains without at least one shot of snow.  Beartooth Pass, at nearly 11,000 feet in elevation, was closed to vehicular traffic up until the day we needed to cross it.  Finally, on June 3rd, hours after it opened, we ascended to the top.  Snow was falling, as was the thermometer in the car as we climbed.  At the top, the temperature was 31 degrees, the wind howled, and we dressed in every layer we brought.  We drove through canyons of snow 20 feet deep, as the road snaked its way over the barren top of the pass.  Considered one of the most scenic roads in the Lower 48,  it was a perfect way to cap off the adventure to the Montana and Yellowstone National Park.

The weather at Beartooth Pass finally allowed for some blue sky and clouds, after 31 degrees, snow, and high winds earlier in the day.

The next Delaware Nature Society Eco-trip is to Ecuador to see hundreds of species of birds in the Andes Mountains, where you will have the opportunity to surpass the elevation on the Yellowstone trip.  From 13,000 feet down to about 5,000 feet, sample the best of birding, eco-lodges, food, and natural beauty in one of the world’s most bio-diverse countries.  Sign up today!!!

By Ian Stewart

For over 4 decades Delaware Nature Society has been providing homes for birds in the form of wooden nest boxes. We currently have over 200 boxes spread across the properties we own or help manage and every year literally hundreds of young Bluebirds, Tree Swallows, Chickadees and House Wrens fledge from our boxes. In some years we are pleasantly surprised to open one of our boxes and find nests of unexpected species like Carolina Wrens, Tufted Titmice or even White-breasted Nuthatches.

Adult male Purple Martin at gourd

This year one of our long-standing volunteers, Steve Cottrell, attempted to attract a new and charismatic species to our nesting list – the Purple Martin! The Purple Martin is the largest swallow in North America, and gets its name because the adult males have purplish-blue feathers over their whole body. Females are purple above but pale below and sub-adult males (those hatched the previous summer) look like females but have purple blotches on their breast. Martins are long-distance migrants that spend the winter way down in the Amazon Basin, especially Brazil, and many people across the country eagerly await the return of these shimmering gems each spring.

Purple Martins are widely but patchily distributed across the eastern United States because they tend to only nest in colonies of artificial houses and won’t be found where these aren’t present. Martins are quite fickle however, and many people erect brand-new houses in what seems like an ideal place (away from trees and preferably near a good source of insects) and yet never attract any martins. Steve was one of those unlucky people and had tried to attract martins to his yard for 5 years without success.

Steve in front of the Ashland Purple Martin tower

He therefore decided to donate his three Purple Martin towers to us! Each of these towers is equipped with a dozen plastic nesting gourds which are made of white so they stay cool inside and a large screw cap on the side for easy checking. Steve erected one tower at Ashland Nature Center and two at Bucktoe Creek Preserve near Kennett Square, Pennsylvania.

Steve lowers the martin gourds to check contents

Steve and Delaware Nature Society staff members anxiously watched the towers throughout spring and were thrilled to spot martins perched at all three towers in late April! We had an even bigger thrill last week when we found at least one Purple Martin nest with eggs at both of the Bucktoe towers and then just today, a nest with 5 eggs at Ashland! This is the first confirmed breeding by Purple Martins at both Ashland and Bucktoe!

Steve checking the Ashland gourds for nests

Eggs found in the Ashland tower

We will be checking the gourds each week to follow these nesting attempts and see if we are lucky enough to get any more. Later in the summer we hope to band any nestlings produced to try and track their movements during migration and winter and also see if any return to our sites in 2019!

We will also be banding nestling Purple Martins at their long-established colony at DNS’s Abbott’s Mill site in Milford on June 30th and at Flint Woods Preserve in Centerville on July 11th so check out those programs if you want to see these beautiful birds up close.

And if you want to try to attract them to your own property, check out Wild Birds Unlimited in Hockessin and the Purple Martin Conservation Association’s website at https://www.purplemartin.org/. Be lucky!

By Kristen Travers

April and May showers may bring flowers but for our streams rain can also bring problems. Recent rains have resulted in our streams resembling unappetizing chocolate milk more than the clear clean water that we want to see.

Before many people lived in the Delaware region, most of our area was covered in forests, wetlands and marshes. When it rained most of the rain water would slowly infiltrate (soak) into the ground and into the groundwater. Today our landscape also includes homes, businesses, and shopping centers. Rain water can’t soak through impervious surfaces such as roads, building and parking lots but instead runs over these surfaces picking up contaminants and sediment and quickly flowing into our waterways.

Data on our local streams clearly shows how as stream flow increases during storm events, so does the cloudiness of the water as measured by turbidity – a measure of the relative amount of suspended particles such as sediment.

Bare soil, dirt exposed from poor construction and farming practices, and stream bank erosion caused by excessive flows cause increased turbidity. Muddy water harms aquatic life, smothers habitat, and increases water temperatures. It can also be a health concern to drinking water sources and recreational uses since harmful microbes found in animal and human waste bind to soil particles.

Providing opportunities for rain water to slowly infiltrate into the ground can keep pollutants and sediment out of our waters while reducing flooding

Rainwater and soil are assets that should be kept in place:

  • Soak it Up: Add native shrubs, trees or perennial plants who’s deep root systems help to break-up soil and promote infiltration, while also holding the soil in place.
  • Cover it Up: Cover bare soil with mulch and more importantly plants!
  • Prevent It: Minimize chemical use on lawns and in our houses, don’t mow right up to the creek, and pick up after your pets.

Thank you to the volunteers involved with the Delaware Nature Society Stream Watch, White Clay Wild & Scenic program, and Nature Conservancy Stream Stewards for their dedication to monitoring and improving the health of our waters.