Birds

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!

Ian Stewart

Sparrows are a mystery to most non-birders (and many birders too!) and it’s not hard to see why. The great majority of them are small, brown streaky birds that at this time of year are usually just glimpsed as they disappear into a tangle of undergrowth, so much so that sparrow sightings often get lumped into the catch-all category of ‘Little Brown Bird’ (hastily scribbled as ‘LBB’ in field notebooks from here to Alaska).

This is a great pity as sparrows are an under-appreciated group of birds in my opinion, and Delaware is awash with them during the winter because several species that breed as far away as northern Canada flood into our area and flock together with our resident sparrows. Tangled brush piles and weedy fields might not be attractive to an average human but they are very popular with sparrows who love to scuffle through them in search of seed as well as take cover in them if a hawk appears. On a good winter’s morning you might see more than half a dozen species of sparrow just by slowly walking along the edges of these brush piles and fields and waiting for them to appear.

A simple first step to identifying sparrows is to look at their breast as this lets you place them into one of two broad categories: those with streaked breasts and those with unstreaked breasts. The collage below is composed of sparrows banded during DNS’s Bird Conservation Program and up close you can see the differences between species in breast patterning, as well as the eyebrow stripes, moustaches and thin crown stripe found in many sparrows.

Top row (L to R). Song, Fox, Savannah 2nd row. Lincoln’s, Field, American Tree (showing ‘stickpin’ in breast) 3rd row. Swamp, Chipping (winter), Slate-colored Junco 4th row. White-crowned, White-throated (adult), White-throated (immature)

The collage below shows the diversity of sizes, shapes and colors seen in sparrows’ beaks. For example, the beak of Song Sparrows is intermediate in length and depth while Fox Sparrows have a short but stout beak and both Lincoln’s and Swamp Sparrows have long, thin beaks. Some sparrows have all-brown beaks while others have beaks that are gray (White-throated), orange (Field), pink (Junco) or jet black (Chipping Sparrow during the breeding season). The American Tree Sparrow has the most distinctive beak of all, being dark brown above but yellow below. There is also quite a lot of variation in the angle of the forehead, the size of the eye, and the curvature of the upper beak.

Top row (L to R). Song, Fox (with 2 ticks!) and Field 2nd row. Chipping (summer), Chipping (winter), Savannah 3rd row. Lincoln’s, Swamp, American Tree 4th row. White-throated, Slate-colored Junco, White-crowned (immature).

Hopefully these photographs have convinced you that sparrows are more different and beautiful than you had thought. My advice is to slowly explore the undergrowth on a crisp, still winter’s morning and try to get a good look at every species you see. Rest assured, you will be rewarded!

 

Ian Stewart

American Goldfinches are one of my favorite birds. Their scientific name, Spinus tristis, translates as ‘Sad bird of thorn bushes’ and derives from their mournful rubber-duck like ‘squeak’ call. Personally, I think this name is unfair, as Goldfinches always seem such happy, colorful characters (like the female pictured below) with their jaunty, bouncy flight and excited twittering. They are common birds which can lead to them being overlooked and yet they have two major surprises under their wing.

The first is that they breed very late in the summer. Once you get past mid-August only a handful of birds are still breeding in Delaware but the Goldfinch is one of these select few, along with the related Indigo Bunting and Blue Grosbeak. The main reason we think Goldfinches breed so late is that they feed their young entirely on seeds, rather than invertebrates like almost all small birds, so they have to delay breeding until the seed heads begin to appear. The favorite food of Goldfinches includes Purple Coneflower (Echinacea purpurea) and Wild Bergamot (Monarda fistulosa), as well as a range of native and unfortunately, non-native, thistles.

Goldfinches build beautiful, densely-woven nests of fibrous materials such as thistle down and grasses in which they lay 2-5 bluish-white eggs (nest photographed at Bucktoe Creek on July 23).  The nestlings develop in around 2 weeks and fledge resembling duller versions of their parents with brownish wing bars and dark beaks (nestlings photographed in a different nest on August 5, just before they fledged).

The Goldfinches’ second surprise is that they are the only finch that molts their body feathers twice a year. Both sexes are a drab yellowish-green in the fall and winter, perhaps to avoid being seen by predators like hawks, but become brighter yellow in the summertime. The males are especially striking with their lemon yellow body, jet-black wings and cap, and white tail flashes.

The sight of a flock of Goldfinches feeding in a field of native thistle is enough to gladden the heart of any birdwatcher, and luckily Goldfinches are quite easy to attract to your yard, even in fairly urban areas. You can buy sock feeders of nyjer seeds or tube feeders made specifically for Goldfinches with thin seed ports. Since Goldfinches have such small pointed beaks they are the only common bird in our area that can reach inside and pick out the nyjer seeds. They will also happily eat black oil sunflower seed from a generic tube or platform feeder which has the added benefit of attracting other birds too. Better still, try planting some patches of Coneflower or native thistle in your yard and watch them feed how nature intended!

By: Tim Freiday, Middle Run Project Coordinator

The group of DelNature staff and volunteers get ready to set off on the annual Bio-Blitz in Middle Run Natural Area.

On Sunday, September 3, 2017, Delaware Nature Society held the annual Bio-Blitz at Middle Run Natural Area. Although rainy at 6:00 am, the skies cleared by 7:00 am and it turned out to be a very productive day with over 200 different species of organism recorded. In the park, 88 species of birds were recorded. Some of the highlights were 20 species of warbler including a Brewster’s Warbler (a rarely seen hybrid), Nashville, Tennessee, Blackburnian, Cape May, and Black-throated Blue and Green Warblers. We had birds everywhere we looked, and had some great views of many. The girdled Bradford Pears continue to provide quality looks at some real quality birds, with American Redstarts, Tennessee, Magnolia, Black-and-white, and Chestnut-sided Warblers perching alongside much larger Brown Thrashers and Gray Catbirds. We also had a continuing Alder Flycatcher who “pipped” only a few times, and Veery were around today. Surprisingly, a nocturnal Common Nighthawk was also flying around in the late morning.  Check out the close-up Northern Flicker below!

 

All of the checklists for the day in chronological order are at the links below:

http://ebird.org/ebird/view/checklist/S38987553

http://ebird.org/ebird/view/checklist/S38976751

http://ebird.org/ebird/view/checklist/S38984241

There have been some excellent photos of some of the fall migrant warblers being posted on the Middle Run flickr account by the likes of Hank Davis and Derek Stoner. You can check out those pictures by following this link:

https://www.flickr.com/photos/middlerunbirding/

Around a 100 insects were identified at least to the family level with the help of UD entomologists Ashley Kennedy and Adam Mitchell. Some highlights from the arthropod realm include a Spiny Oak Slug caterpillar, Hickory Tussock Moth, Locust Borer, Ornate Plant Bug, Cicada Killer, Green Darner and many more. There was a very bright Red Admiral butterfly which must have just emerged. Participants learned about the food web of arthropods in our area, and got a glimpse of how complex it really is. Middle Run has a healthy mix of arthropods, with many predatory spiders and insects signifying an abundance of herbivorous insects. No wonder the birds like it here so much! It’s also not surprising that there are so many insects given the diversity and abundance of plants at Middle Run. At least 50 different species of plants were identified today, with many beneficial native species. Some are very showy and are flowering right now, like the Evening Primrose. We only found a handful of reptiles and amphibians today, but there were some nice ones such as Black Racer, Garter Snake, and American Toad.

Hickory Tussock Moth

Hickory Tussock Moth

This year’s BioBlitz showed how truly special and utterly important Middle Run Valley Park is for the multitude of life that our region supports. From the local birds and insects to the long distance migrants that refuel here, to the people that come and unwind by taking in the natural world Middle Run is a true gem that we should all be grateful for. In appreciating the importance of Middle Run we are shown the importance of conserving natural lands everywhere, and we are called to action to protect our natural world.

This past Tuesday was the first Tuesday Morning Bird Walk at Middle Run of the fall 2017 season. These walks are free and open to the public, and Delaware Nature Society staff will lead them each Tuesday at 8am through October.  The walks are sponsored by New Castle County Parks.  Come join us as we appreciate birds and nature!

Happy Birding!