Ashland Nature Center

Ian Stewart

A major analysis published last week (Rosenberg et al. 2019, Science, downloadable by scrolling down here) makes depressing reading for anyone interested in birds or in nature in general. A team of leading North American researchers analyzed almost 50 years of data from multiple sources and calculated that about 3 billion birds (= 3 thousand million!) have been lost from the continent since the 1970s. This staggering total suggests that over 1 in 4 North American birds have disappeared in less than half a century. Some groups of birds have been hit especially hard, with over half (53%) of all grassland birds disappearing as more and more of their habitat is plowed under to make way for agriculture or development. Shorebirds are close to the hearts of many Delawareans since they famously stop to refuel in the Delaware Bay on their way north to breed and yet these are among the most strongly declining birds, with a drop of 37% in 50 years. The bejewelled warblers, those colorful songbirds which symbolize migration for many birders, have dropped by 38%.

A Rusty Blackbird, one of several rapidly declining bird species

Some of the report’s findings simply confirmed the sad stories recounted by long-time Delaware birders that species which used to be merely uncommon are now very hard to find, like the Rusty Blackbird. However, some of the other findings were much more surprising and perhaps more troubling because they revealed serious declines in groups of birds usually taken for granted as ‘common’ like blackbirds (44%), finches (37%) and sparrows (38%). It is probably not a coincidence that almost all of these species feed their nestlings on insects, another major taxon that has seen dramatic declines.

A male Red-winged Blackbird breeding in a meadow at Coverdale Farm Preserve.

The report wasn’t all doom and gloom however. Waterbirds (ducks and geese) have shown a resurgence (+56%) thanks to better management and protection of wetland and marsh habitats based on millions of dollars raised by the sale of Duck Stamps to hunters and non-consumptive users as well as federal and state wildlife grants. Several birds of prey have also rebounded thanks in part to the ban on DDT, including a remarkable 300% increase in the numbers of the fish-eating Osprey. These success stories show that bird declines can be reversed if we act quickly enough to protect and preserve their habitats since the loss or degradation of their breeding, wintering or migratory habitats is the root cause of almost all bird declines.

Birds provide many ecological benefits like seed dispersal, pollination and control of arthropod pests but are also a source of everyday enjoyment for millions of North Americans who enjoy bird watching or feeding birds. Birds are also an excellent way to stimulate an interest in nature, especially among children, because they are active during the day and present in all four seasons, and many have colorful plumage or attractive songs. In short, birds are perhaps the most visible and recognizable component of most North American ecosystems, and if they are in such a serious decline then many other parts of the ecosystem probably are too. A loss of 3 billion birds in less than 50 years is simply not sustainable.

A mixed flock of sparrows in a typical suburban yard in winter. One day, this may not be a common sight.

Although the challenges birds face are large and on a continental scale, there are several fairly simple ways that you can help birds in your own yard or neighborhood. Try this excellent list from Cornell University!

 

Ian Stewart & Lori Athey

Now that spring is here many Delawareans are enjoying the colorful wildflowers blooming in their backyard, local parks and road sides. Unfortunately, the great majority of those currently flowering are alien weeds which were either deliberately or accidentally introduced by Europeans. These plants found themselves in a new environment with few or no natural enemies and spread rapidly across our area. Each weed produces hundreds if not thousands of seeds and an entire backyard can be riddled with them in just a few years.

The three most common yellow-flowered weeds have been covered in a previous blog (http://blog.delawarenaturesociety.org/2015/05/06/the-not-so-mellow-yellows/) and this follow-up blog highlights some of the other visually-appealing wildflowers that people may not realize are aggressively invasive aliens.

Three common backyard weeds stay low but spread rapidly to form sun-blocking carpets that inhibit or prevent the growth of any native seeds beneath them. Speedwell (Veronica sp.) is one of the first wildflowers to emerge and its four-petaled circular blue flower can be seen as early as March. There are several species of speedwell but most are alien. Ground ivy (Glechoma hederacea) produces dozens of tiny purple flowers and spreads by underground rhizomes which makes it especially difficult to control since pulling one part of the plant will not suffice. Clover (Trifolium sp.) is particularly common in farm fields, perhaps because it may have been introduced as livestock feed, but is now ubiquitous in urban and suburban settings. Clovers have three leaves, each with a distinctive white chevron, though finding one with four leaves may bring you luck! There are two sister species, the red and white clover, which are named after the color of their flower.

Speedwell (Left) and Clover (Right)

Ground ivy

Two striking members of the Mint family also stay quite low to the ground but are easily seen because they often grow in large patches. Purple deadnettle (Lamium purpureum) and henbit (L. amplexicaule, also known as clasping deadnettle) often grow together in fields and backyard although the former is much more common.

purple deadnettle

Henbit

Finally, three conspicuous white-flowered members of the Mustard family are widespread throughout the Piedmont. Garlic mustard (Alliaria petiolate) and roadside penny-cress (Thlaspi alliaceum) are both knee-high single-stemmed weeds which form large clumps in sunny areas, while hairy bittercress (Cardamine hirsute) is quite a bit smaller and branches into multiple small flowers.

Garlic mustard

roadside penny-cress

Penny-cress up close

Purple deadnettle (on left) and hairy bittercress (on right)

These alien wildflowers are especially problematic because they bloom in early spring and may have already produced seeds before householders begin mowing. Although it is an uphill battle, most weeds can be controlled by hand-pulling them before they go to seed, especially if the whole root system is removed.  Repeated early mowing or weed-whacking will deplete the weeds’ resources before they even flower. If you have a large yard or field an alternative option is to gradually convert it into a meadow with long grass and native wildflowers which is left standing throughout the winter and early spring. This helps to restrict early-growing weeds like ground ivy and deadnettle by reducing the amount of sunlight they receive.

Once you have removed the alien weeds you can replace them with native wildflowers which are much better for wildlife, especially our declining pollinator insects as well as the animals that feed on them. A perfect opportunity is the Delaware Nature Society’s Native Plant Sale which is held at Coverdale Farm in Greenville. It starts with a member’s-only day on Thursday May 2nd (1pm-7pm; though you are welcome to attend and join in person) and is then open to the public Friday May 3rd (3pm-7pm) and Saturday May 4th (9am – 3pm). Admission is free and there will be plenty of staff and volunteers present to answer any questions about plants and help you load them into your car!

The full catalog is online here but just to whet your appetite, here is a selection of groundcover plants which are tough and fast-growing and have a decent chance at outcompeting those pesky weeds!

Dry sunny location

Andropogon virginicus (Broom Sedge) grass

Coreopsis verticillata (Whorled Tickseed) perennial

Geum fragarioides (Barren Strawberry) evergreen perennial

Phlox subulata (Moss Phlox) evergreen perennial

 

Dry shaded location

Antennaria plantaginifolia (Woman’s Tobacco Pussytoes) semi-evergreen perennial

Chasmanthium latifolium (Wild Oats) grass

Geranium maculatum (Wild Geranium) perennial

Polystichum acrostichoides (Christmas Fern) evergreen fern

 

Moist shaded location

Asarum canadense (Wild Ginger) perennial

Osmundastrum cinnamomeum (Cinnamon Fern) fern

Phlox stolonifera (Creeping Phlox) perennial

Zizia aurea (Golden Alexanders) perennial

 

Moist to wet sunny location

Carex cherokeensis (Cherokee Sedge) grass

Eupatorium perfoliatum (Boneset) perennial

Iris versicolor (Blue Flag) perennial

Panicum virgatum (Switchgrass) grass

 

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