Bucktoe Creek Preserve

Ian Stewart

Every fall birdwatchers throughout the eastern United States wait anxiously by their computers for an email containing this year’s Winter Finch Forecast http://jeaniron.ca/2018/wff18.htm. For almost 20 years now Ron Pittaway, a former naturalist at Algonquin Provincial Park in Ontario Canada, has been predicting whether this group of small, seed-eating birds that breed in Ontario remain there during the winter based upon how successful the cone crop was that summer. Simply put, if the trees produced a lot of seeds then the finches will have enough food to survive the winter and will stay up north, but if the cone crop was poor they will have to fly south to find food and will ‘irrupt’ into the northern United States or maybe even further south.

Remarkably, Ron’s forecast is usually correct so local birders were thrilled to read his prediction that finches would be travelling south this winter because the cone crop in Canada was poor. Sure enough, about 2 weeks ago people throughout Delaware and south-eastern Pennsylvania started seeing flocks of Purple Finches at their feeders! These look a bit like our resident House Finches but the males are raspberry-colored over their whole body while the females and immature birds are heavily streaked below and have white stripes on their face. Purple Finches are attracted to black oil sunflower seed, especially if it is piled on a horizontal platform feeder.

A flock of Purple Finches at a platform feeder

The Delaware Nature Society’s bird banding program has confirmed that this is an irruption year for Purple Finches. So far this fall we have banded no fewer than 40 of these birds, compared with just 5 in the winter of 2016 and none at all last winter.

Male House Finch (left) and Purple Finch (right) banded this fall

Now people across our region are seeing a second species of winter finch at their feeders, the Pine Siskin. This small, streaky finch has yellowy-green wing patches and a very thin beak which it uses to pry nyjer (thistle) seeds from finch socks or hanging feeders with narrow holes.

Pine Siskin feeding on ground (Photograph by Hank Davis)

The thin beak of a Pine Siskin

Whisper it quietly but this winter we may see two more highly-prized finches which usually remain far to our north. The first of these is the Redpoll, a small streaky finch with a red forehead that flocks in weedy fields and congregates at nyjer feeders. The second is the majestic Evening Grosbeak, a striking yellow, black and white version of our familiar Cardinal which is attracted to platform feeders baited with sunflower seed

All of the above winter finches readily come to bird feeders and best way to attract them to your yard is to provide a variety of seeds in different types of feeders, like hanging tubes of either black oil sunflower or nyjer coupled with platform feeders filled with sunflower seeds or millet. Try visiting Wild Birds Unlimited in Hockessin for a large selection of seed mixes and feeders.

Flock of Siskins at a hanging feeder (Photograph by Hank Davis)

Another two irruptive winter finches that are much sought after by birdwatchers are the crossbills. The Red Crossbill tends to occur in pines and the White-winged Crossbill in spruces and larches. These intriguing birds are unique in that their upper and lower beaks are ‘crossed’ and are used to prise open pine cone scales to get to the seed within. Crossbills do not usually come to seed feeders but if you want to attract them you could try pulling the old ‘salt block trick’. Apparently they are very fond of salt and can be attracted to platform feeders using chunks of the salt blocks that farmers leave out for cattle and horses!

The winter of 2018/2019 could be a memorable year for winter finches in Delaware, so be sure to take full advantage of it. The best places to search are weedy fields and stands of cone-bearing pine trees in public parks or cemeteries, but you are just as likely to see them at the feeders in your back yard or the Ashland Nature Center bird blind. And maybe consider dropping by our free bird banding sessions to see if you are lucky enough to see a winter finch up close. Bird banding takes place through November every Monday at Ashland Nature Center and every Wednesday at Bucktoe Creek Preserve near Kennett Square, 8am-11am.

 

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!

By Ian Stewart

Delaware Nature Society has over 200 nest boxes spread around the properties we own or help manage which we installed to provide nest sites for a variety of birds. Every summer these boxes are monitored by a team of volunteers who track over 100 nesting attempts by 5-6 bird species (and we are always looking for more people to help with this – please get in touch if you’d like to get involved!). You’d be wrong to think the boxes stand idle throughout the winter however – it’s just that most of the action now takes place at night!

Several birds often roost in them during the winter, including Screech Owls, Eastern Bluebirds and some woodpeckers, which they probably do to protect them from the elements such as wind and rain. It is likely several degrees warmer inside a nest box than outside of it and for a small bird on a very cold night this could be the difference between life and death. Bluebirds take this a little further and are famous for ‘bundling’, where several birds squeeze into the same box for the night, probably keeping each other warm with their body heat.

A male bluebird entering a nest box

A male bluebird entering a nest box in winter

This year we’re making a special effort to check our boxes during the winter too. Sometimes it’s obvious that birds have been roosting in our boxes as they leave their droppings behind. The droppings in the photo below were almost certainly from a bluebird that has been eating Oriental Bittersweet. Bluebirds usually eat insects but at this time of year these are hard to find so they switch their diet to berries, and this exotic invasive vine is one of the few local plants that still has berries on it in February. You can help bluebirds in winter by planting berry-producing native bushes and shrubs such as Winterberry, Viburnums and Hollies. We will be following these boxes all through the year to see if bluebirds end up nesting in the same boxes that were used in winter.

Bluebird droppings inside a nest box

Bluebird droppings show they have been using this nest box

It’s also worth checking nest boxes in winter for less-desirable occupants. About 10% of our nest boxes are occupied by white-footed or deer mice during the winter. These nocturnal mice build fluffy nests inside boxes and sleep in them during the day. We always dump out mice and their nests during the winter, which may seem unkind but if left in place their urine and feces can damage boxes or carry disease, and birds won’t use boxes already occupied by mice. If you do this yourself, don’t use your hands to dislodge mice and their nests in case you pick up any disease or get bitten, but instead gently ease out the box contents with a stout stick.

Two deer mice fast asleep in this box

Two deer mice fast asleep in this box

This box at Coverdale Farm Preserve contained a furry nest with no fewer than 15 uneaten hickory nuts, which was interesting as this is not a common tree at the Preserve. These had probably been stored in the box by a Flying Squirrel, a nocturnal mammal which does not hibernate and requires food all winter. The squirrel cached the nuts here to provide a food supply for later in the winter, so to be sure the little guy wouldn’t go hungry we left the nuts below the box.

Hickory nuts cached in this nest box by a flying squirrel

Hickory nuts cached in this nest box by a flying squirrel

So just because you never see anything going inside your nest boxes in winter, don’t assume they aren’t being used!

Autumn among the beeches

Ian Stewart

If life is getting you down or you’re feeling particularly stressed why not take a gentle afternoon stroll through a beech wood? Walking through a beech wood in the fall is a serene experience that will instantly melt away your troubles. And if you look closely, the beeches have a few surprises in store…..

The American Beech (Fagus grandifolia) is a fairly common tree across almost all of the eastern United States and is easily recognized by its smooth, pale gray bark and its above-ground ‘knees’ formed by the tops of its shallow roots. We have several stands of old, large beech trees around our DNS sites because early settlers tended to leave them alone as they often grow on hillsides which aren’t attractive sites for home building or farming, and also because their hard wood is difficult to cut.

At this time of year the ground beneath a beech wood is littered with a carpet of their golden leaves and if you wait long enough you will see a variety of mammals and birds rustling though them in search of fallen beech nuts. These distinctive triangular nuts emerge in pairs from their tough, furry husks when ripe and are beloved by deer, squirrels and Blue Jays and were apparently the favored food of the extinct Passenger Pigeon. Beech nuts are edible to humans once they have been peeled although they are apparently bitter and may even be toxic in large quantities so we do not recommend that you eat them.

Part of the reason beech woods are so attractive to walk through is that they are remarkably open, with very little understory of bushes or shrubs to navigate through. This is because beech trees are thought to be allelopathic, meaning they exude a chemical into the soil around them which inhibits the growth of other plants. Sometimes the only plant you see growing near a beech tree is a ring of ‘root sprouts’ growing around its trunk, which is a direct way through which beech trees spread in addition to their nuts.

Still, despite their placid outward appearance beech woods are tinged with intrigue. If you get down on your hands and knees you will notice that most of the trees have a circle of mysterious brown weedy stems around their base. These are known as Beechdrops (Epifagus virginiana) and are among a handful of plants that don’t photosynthesize but instead live parasitically by burrowing into the roots of beech trees and extracting their nutrients.

So please take the time to explore a beech wood this fall, but be sure to appreciate the small struggles going on underneath these giant trees!