Ashland Nature Center

Ian Stewart

These are the opening words of the poem ‘To a mouse’, written by the legendary haggis-eating Scottish poet Robert Burns in 1785 (which also contains the famous line oft-paraphrased as ‘The best-laid schemes of mice and men go often askew’). Although this is an apt description of mice it is also used to refer to all manner of small, obscure and reclusive animals and feather mites fit perfectly into this category.

Most people have never heard of feather mites which is hardly surprising. They are tiny brown arthropods which spend most of their lives flattened along the vanes of bird wing feathers where they were assumed to scavenge on feather debris and oily secretions and perhaps even rasp away at the feathers themselves. However, a remarkable study published last summer (Doña et al. 2018) examined the contents of mites’ stomachs using high-power microscopy and DNA analysis and found that their main food was fungi, and perhaps also bacteria and oil produced from the birds’ preen gland. Whether this means feather mites harm their hosts or are simply commensal remains to be seen.

Birds are assumed to acquire feather mites through physical contact with their parents while they are still in the nest, although they could also pick up mites from bumping into other birds at feeders or sharing the same dust bathing sites. Mites are quite easy to see if you are holding open a bird’s wing although with the naked eye they just look like a cluster of small dots (shown below).

We gained a whole new appreciation for these creatures when Shannon Modla of the University of Delaware kindly photographed some Gray Catbird feather mites under a light microscope. The magnified views show that they are long and thin with two pairs of legs at the front of their body and two pairs at the back (image below). The darker mites on the left and below are probably older mites with a hardened exoskeleton while the paler one on the right is probably a younger mite that has just molted.

Shannon was then able to view them under a powerful electron microscope and got some incredible images of their head as well as an egg (below).

To try to gain some insights into the biology of these enigmatic creatures we have been scoring the number of feather mites present on birds handled during the Delaware Nature Society’s Bird Banding project. Our simple questions were which bird species are most likely to have mites and whether the number of birds with mites varies according to the time of year.

Our first finding was that feather mites are quite common. We examined 448 birds belonging to 48 species and found that almost half of them (203 birds from 37 species) had mites on at least one of their wing feathers. We also found the proportion of birds with mites varies a lot between species. Over 75% of the Slate-colored Juncos, House Finches and Downy Woodpeckers that we examined had feather mites yet fewer than 15% of Ruby-crowned Kinglets, Common Yellowthroats or House Wrens had them. We also found that the proportion of birds with mites stayed quite consistent across the year with a noticeable peak in May.

This year we will be gathering more data on mites from the birds we band and then try to figure out why some birds are more likely to have mites than others, and why some have lots of mites while others have very few. Is it related to their body size perhaps, or how social they are, or maybe whether their beak is small and pointed enough to preen away the mites? So watch this space for updates on this new and fascinating DNS research project!

DNS has plenty of birding opportunities coming up soon, so sign up and enjoy the outdoors!

The Great Backyard Bird Count ~ Coverdale Farm Preserve

The Great Backyard Bird Coount: Kent County Tour ~ Abbott’s Mill Nature Center

Owls and Other Winter Raptors ~ Ashland Nature Center

 

By Joe Sebastiani, Ashland Nature Center Manager

Delaware Nature Society graduated fourteen “Certified Naturalists” in December, awarding those who successfully completed the year-long Naturalist Certification Series and the associated field journal.  In the past 12 years, over 300 people have taken this class which focuses on gaining a foundation for the study of nature in Delaware.

The Naturalist Certification class visits Teardrop Pond in Blackbird State forest with Jim White, Herpetologist and Delaware Nature Society Director of Land and Biodiversity.

Our graduates this year include: Jen Smyth, Suzanne Blair, Noreen Cambell, Brooke Cherry, Ted Gatanis, Lana Glass, Bea Kaplan, Laurie Linton, Emily Magnani, Christen Majewicz, Diane McGovern, Katie Pollock, Kayla Krenitsky, and Tere Schubert.  Delaware Nature Society congratulates them on their attendance and devotion to completing the field journal!

The first field trip of the year was to Coverdale Farm Preserve to study local mammals.  Register for the 2019 class, which begins on March 21st!  Photo by Noreen Campbell.

Students attend lectures and field trips revolving around 8 topics which include the study of: Mammals, Terrestrial Ecosystems, Reptiles and Amphibians, Birds, Wildflowers, Insects, Trees and Shrubs, and Aquatic Ecosystems.

The 2019 Naturalist Certification Series is ready for registration!  Here is a flyer to review about the class or send to your friends.  If you are a school teacher, by completing the class, you qualify for 60-hours of inservice credit.

A student in the Naturalist Series holds a Northern Pine Snake in the Herpetology lecture. Photo by Jim White

In one year, you will gain experience with tracking mammals, wade into a wetland at night in search of frogs, learn how to compare the ecology of different forests, evaluate stream ecological health, identify trees, shrubs, and wildflowers, understand various insect orders and their role in the environment, and band birds with an ornithologist.  In the process, you’ll make new friends who are interested in the outdoors, botany, wildlife, and the environment.  We hope you can join us for the 2019 Naturalist Certification Series.

In the meantime, here are some “Naturalist Quotes” for you to ponder and enjoy…

“We are all meant to be naturalists, each in his own degree, and it is inexcusable to live in a world so full of the marvels of plant and animal life and to care for none of these things.” ~ Charlotte Mason

“Since we humans have the better brain, isn’t it our responsibility to protect our fellow creatures from, oddly enough, ourselves?” ~ Joy Adamson

“Happy indeed is the naturalist: to him the seasons come round like old friends; to him the birds sing: as he walks along, the flowers stretch out from the hedges, or look up from the ground, and as each year fades away, he looks back on a fresh store of happy memories.” ~ John Lubbock

“Even the lifelong traveler knows but an infinitesimal portion of the Earth’s surface. Those who have written best about the land and its wild inhabitants…have often been stay-at-home naturalists…concentrating their attention and affection on a relatively small area.” ~ Edwin Way Teale

“The clearest way into the Universe is through a forest wilderness.” ~ John Muir

“Delight itself, however, is a weak term to express the feelings of a naturalist.” ~ Charles Darwin

By Jim White: Senior Fellow for Land and Biodiversity

It’s not every day that a new species of animal is found in Delaware. In fact, it is very rare indeed. However, in the summer or 2015 Adam Mitchel, a PhD candidate at the University of Delaware did just that. While collecting insects in a meadow at the Ashland Nature Center for his PhD research project on the effects of invasive alien plants on native insects, Adam found several insect specimens that he could not identify.  After examining them under a microscope in his lab he could only identify them as insects belonging to the Insect Order Thysanoptera commonly called Thrips (both the singular and plural of the noun has an (s). The Order Thysanoptera are minute insects with reduced wings, most species being around 1mm long. All but a few use sucking mouth parts to feed on the stems of plants. Several species are considered pest as they can damage crops and other plants. However, the vast majority of the 6,000 or so species are not pests to humans and are valuable members of the food chain.

This species of Thrips, new to science, was discovered at the Ashland Nature Center by entomologist Adam Mitchel. It has no English common name, but scientifically it is called Konothrips polychaeta.  Photo courtesy of Dr. Mitchel, from Goldarazena et al. (2017).

These tiny insects are not often studied unless they are considered pests and information on the many non-pest species is limited. Lucky for Adam, a professor from Belgium, Dr. Arturo Goldarazena…an authority on Thrips, was visiting the University of Delaware. Adam approached Dr. Goldarazena and asked if he would look at some of the Thrips specimens that he collected.  It did not take long for the professor to realize that he had never seen some of the specimens and declared that Adam might have discovered a new species. Adam agreed to give Dr. Goldarazena the specimens to study back in Belgium.  After an exhausting investigation the new species was described and published in Goldarazena et al. (2017). Its official scientific name is Konothrips polychaeta which loosely translates to “hairy tenacious woodworms”.  At this time, there is no common English name for this new species of Thrips. However, I propose to call it Mitchell’s Thrips.

Andropogon virginicus is the host plant for the newly discovered Thrips. Is the new species found wherever this plant exists??? Photo courtesy of Dr. Mitchel, from Goldarazena et al. (2017).

Finding a new species of animal or plant is a dream for biologists – finding them right under our noses in places like Ashland is even more exciting. Adam found the new species inside the flowers of the broom-sedge, Andropogon virginicus but he believes that Konothrips polychaeta probably feeds and breeds on other grasses and sedges that are abundant in the meadows and marshes at the Ashland Nature Center and beyond. These meadow and marsh habitats have been restored and maintained at several of Delaware Nature Society sites as part of the land and biodiversity management program. The program is dedicated to the conservation and preservation of native species and their habitats.

Dr. Adam Mitchel is a native Delawarean and discovered the new species of Thrips while he was a PhD candidate at the University of Delaware. Photo courtesy of Dr. Mitchel.

Dr. Adam Mitchel is a native Delawarean. He attended St. Marks High School and received his undergraduate degrees at the University of Delaware in Wildlife Conservation, Entomology, Plant Protection, Agriculture and Natural Resources (quad majored), and earned his master’s degree in Fish and Wildlife Management at Montana State University. Adam returned home to University of Delaware to obtain a PHD in Entomology and Wildlife Ecology (concentration: Entomology) at the time of the discovery of the Thrips. Adam is now employed as an Assistant Professor of Entomology at Tarleton State University in Texas.

Reference:

Goldarazena A, Mitchell AB and T. Hance (2017) Konothrips polychaeta sp.n. from Delaware, North America, with a key to the three species of this genus. Zootaxa 4341: 445-450.

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.