Bucktoe Creek Preserve

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By: Ian Stewart, Ornithologist

Delaware birders are out in full force at this very moment and one of their main targets is migrating warblers. Warblers are small, colorful songbirds which flit actively from tree to tree picking off insects with what the field guides usually describe as thin pointed beaks (also known as ‘bills’). But are warbler beaks really all small and pointed? We have handled several warblers during the Delaware Nature Society’s bird banding project and a closer view reveals a surprising amount of variation in the size, shape and color of their beaks.

The Northern Parula is one of the smallest warblers and has a very thin and pointed beak which it uses like fine tweezers to glean tiny arthropods from leaf surfaces.

Northern Parula

Northern Parula

The Prairie Warbler also has quite a sharp beak but it is shorter and more rounded than the Parula’s. Its beak is jet black unlike many of the other warblers which have brownish two-toned beaks with the upper mandible being darker than the lower.

Prairie Warbler

Prairie Warbler

The Mourning Warbler has a fairly substantial bill for a warbler. Mourning Warblers tend to feed on or near the ground and perhaps eat larger insects or grubs.

Mourning Warbler.

Mourning Warbler.

Waterthrushes are relatively dull, streaky warblers that live along streams where they pick arthropods from the surface of the mud and rocks. There are two species, the Louisiana and the Northern, which look very similar but can be partly distinguished by their beak length. The Louisiana was once known as the ‘large-billed waterthrush’ and you can see from these photos that their beak is indeed longer and a little heavier than the Northern.

Louisiana Waterthrush

Louisiana Waterthrush

Northern Waterthrush

Northern Waterthrush

The American Redstart has an unusual beak for a warbler. When seen from above (or more commonly, from below!) its beak is broadly triangular and looks more like that of a flycatcher than a warbler (see the photo below). It’s probably no coincidence that Redstarts often feed by leaping off branches and grabbing insects in mid-air. The conspicuous bristles around the base of their beak may help them trap these insects.

American Redstart (left) and Northern Waterthrush Beaks

Comparison of beak thickness in American Redstart (right) and Northern Waterthrush (left)

Another warbler with an unusual beak is the Yellow-breasted Chat. The Chat is a large, stocky bird that some people do not even consider a warbler, and it has a correspondingly huge, stout beak with a rounded upper mandible. Chats have such a big beak that they can chomp on insects such as grasshoppers that that are too big for the other warblers and can also eat berries.

Male Yellow-breasted Chat

Male Yellow-breasted Chat

Insects and other arthropods are the staple food of all warblers and yet the variation in the size and shape of their beaks suggests that each species eats different prey. This partly explains why some species are usually seen actively hunting in the upper canopy of either deciduous or pine trees while others creep slowly around on the ground, perhaps waiting for an arthropod to emerge. Warblers are passing through Delaware as we speak so next time you see one, take a good look at its beak and see if you can guess what it feeds on!

By Ian Stewart, Ornithologist

Bird banding is in full swing at both Ashland Nature Center and Bucktoe Creek Preserve and our mist-nets are becoming dominated by Gray Catbirds! Gray Catbirds (Dumetella carolinensis) are grouped with Northern Mockingbirds and Brown Thrashers as ‘mimic-thrushes’ as all three are slender thrush-like birds with long tails and loud, elaborate songs. Indeed, catbirds get their name because of the peculiar cat-like ‘miaow’ call they often give while hidden low in a bush! Catbirds are by far the most common of the three mimic-thrushes however, and can be so abundant that many birdwatchers don’t give them a second glance. This is a pity, because catbirds have several interesting features which are particularly obvious when you are holding them during the banding process.

The first of these is the conspicuous rictal bristles around the base of their bill. Several other groups of birds have rictal bristles (especially flycatchers) and although their exact purpose is unknown they are thought to either have a sensory function or to prevent captured insects from scratching a bird’s eyes while they are being held in their bill.

Four rictal bristles can be seen at the base of this Gray Catbird's bill.

Four rictal bristles can be seen at the base of this Gray Catbird’s bill.

The second distinctive Catbird character is their crimson ‘crissum’. This is the patch of feathers underneath their tail which isn’t always easy to see in the field as Catbirds tend to stay fairly low to the ground. The third interesting plumage character of Catbirds, which can also be seen in the picture below, are the fairly obvious growth bars in their outer tail feathers. Growth bars appear as alternating light and dark bands and each pair of bands represents one 24 hour period of feather growth.

Underside of a Gray Catbird showing the crimson crissum and growth bars in the outer tail feathers.

Underside of a Gray Catbird showing the crimson crissum and growth bars in the outer tail feathers.

Not surprisingly, Catbirds were by far the most frequently caught species during the pilot banding project we conducted last summer at Ashland and Bucktoe. In just 3 months we caught 152 catbirds, of which 87 were juveniles likely hatched locally. So far this year we have recaptured 3 of the catbirds we banded last year and hope to recapture even more as the season progresses. It’s truly amazing to think that these 3 birds spent their winter over a thousand miles away in the south-eastern US or the Caribbean and yet came back to the same few hundred acre spots in DE and PA the following year!

The number on this metal leg band showed that this Gray Catbird was banded the previous year.

The number on this metal leg band showed that this Gray Catbird was banded the previous year.

So be sure to take a longer look at a Gray Catbird next time you see one. They are more interesting than you might think!

Public bird banding sessions are held at Ashland Nature Center on Monday and Bucktoe Creek on Wednesday, both from 8am – 11am, though banding does not take place if it is raining or windy, out of concerns for the birds’ safety.

Note that there will be no banding this Monday (May 30th) due to the Memorial Day Holiday.

By Ian Stewart, Ornithologist

Some of the coolest birds we have been catching at the banding stations at Ashland Nature Center and Bucktoe Creek Preserve are the ‘tree-dwellers’: the woodpeckers and nuthatches. These birds aren’t always easy to see during the summertime as they spend most of their day deep in the forest, hugging trunks or branches. However, once you learn to recognize the high-pitched ‘peenk’ of the Downy Woodpecker and the nasal ‘honk-honk-honk’ of the White-breasted Nuthatch you soon realize that both of these birds are quite common year-round.

We have caught and banded 11 Downy Woodpeckers since June and they are a treat to handle. Their bill is thin but strong and they have distinctive tufts of stiff bristles over their nostrils which probably stop chips of wood flying up their nose when they are hammering on trees!

Like several woodpeckers, you can tell what sex adult Downies are by checking out how many red feathers they have on their head – males have a red square at the back of their head but females do not. In most birds you cannot tell what sex juvenile birds are but in Downy Woodpeckers you can – the males have a spotted red cap but the females have a spotted white cap. Try to see if you can spot this next time you are out birdwatching!

Woodpecker collage

In this collage, the Downy Woodpecker in the main image is an adult male. In the lower left corner is a juvenile male, low center is an adult female, and the lower right is a juvenile female.

One morning at Ashland a group of lucky visitors were present when a Downy Woodpecker was captured in the same net as a Hairy Woodpecker! The Hairy Woodpecker is a larger version of the Downy but is much less commonly seen or heard, and the two can easily be confused as they look very similar. If you happen to be holding them both however, the difference is obvious – the Hairy is a bulky, powerful bird that is over twice the size of the dainty Downy.

A Hairy Woodpecker is above, and a Downy Woodpecker is below. Notice the beak of the Hairy...it is about as long as the head is wide. On the Downy, the beak is shorter than the head is wide.

A Hairy Woodpecker is above, and a Downy Woodpecker is below. Notice the beak of the Hairy…it is about as long as the head is wide. On the Downy, the beak is shorter than the head is wide.

We have caught 7 White-breasted Nuthatches so far and one of the first things you notice about them is their long thin, uptilted bill, which they use to pry up pieces of bark to get at the juicy insects beneath. Nuthatches can also be sexed according to their crown color, with males having a black crown and females having a paler, gray crown.

A male White-breasted Nuthatch. The black crown and uptilted bill is easy to see.

A male White-breasted Nuthatch. The black crown and uptilted bill is easy to see.

Even though nuthatches are striking birds at any distance they are even more stunning up close, with a sublime mix of black, white and blue-gray feathers and a distinctive patch of pale brown feathers underneath their tail. Interestingly, even though nuthatches spend a lot of their time climbing up tree trunks in the same way as woodpeckers, their toes are arranged like those of most birds, with three toes forward and one back (although the back toe has a long claw, as seen in the photo below). Unlike woodpeckers however, nuthatches will also climb down trunks and branches, and maybe they need three forward-pointing toes to brace themselves on these downward trips?

Note the underside of the White-breasted Nuthatch, and the very long claw on the hind toe.

Note the underside of the White-breasted Nuthatch, and the very long claw on the hind toe.

If you want to see either of these amazing birds, please visit one of our banding stations and you may get lucky. Alternatively, both of them can easily be attracted to bird feeders filled with black oil sunflower seed, especially during the wintertime.

Ian Stewart will be conducting a Bird Banding Demonstration on Saturday, October 10 as part of our programming at the Big Sit.  The Big Sit is an international competition to find as many species of birds from one location, a 17-foot-diameter circle, during the day this Saturday.  The Big Sit will be held at the Ashland Nature Center Hawk Watch, and we will also be offering nature walks at 10am and 2pm, a 1pm lecture on the Raptors of Fall Migration, and food to keep you going!

By Dr. Ian Stewart, Ornithologist and Naturalist

Thanks to a generous donation, Ashland Nature Center and nearby Bucktoe Creek Preserve are hosting a bird banding project that the public is welcome to visit. Bird banding is an important tool for scientists and conservationists since tagging individuals helps us figure out if they remain in the same site year-round, or in the case of long-distance migrants, where they spend their summers and winters and which routes they take. Basically, birds are caught in fine nets erected along trails then carefully removed and fitted with a uniquely numbered metal band before being released. Because the birds’ welfare is the highest priority, we check the nets every 10-15 minutes and do not operate them on very windy or rainy days. Also, it requires many years of practice with extracting and banding birds before one can be granted a federal license to do so.

A Wood Thrush in a mist-net.

A Wood Thrush in a mist-net.

With the help of a crew of volunteer assistants (Steve, Angie, Kelley and Carol), we have caught over 150 birds from 25 species, primarily Gray Catbirds, Tufted Titmice and Northern Cardinals (and yes, they bite!), but also some really neat birds like Brown Thrasher, Willow Flycatcher and Northern Flicker. We obtain as much data as we can from each bird including its age, sex, body size and molt status to answer questions about how these vary between sites and different habitats. It’s much easier to work out the age or sex of bird species if you are actually holding them, and banding birds helps you notice many things you’ve never seen before. For example, the Tufted Titmouse in the top photo below is an adult, but the one in the bottom photo is a juvenile, as can be told by the yellow eye ring and yellow flanges (the fleshy corners of the beak left over from when it was a nestling).

An adult Tufted Titmouse.

An adult Tufted Titmouse.  Can you see the small tick just above the right side of the eye?

A juvenile Tufted Titmouse.

A juvenile Tufted Titmouse.

Also, the male Eastern Towhee in the bottom photo below was likely hatched last year (2014) since it still has some brown juvenile feathers on its head while the one in the top photo was likely hatched in 2013 or even earlier as it has a solid black head. Look at those amazing red eyes!

An adult Eastern Towhee.

An older adult Eastern Towhee.

A juvenile Eastern Towhee.

A younger Eastern Towhee.

Some features on certain birds are only evident when you see them up close. For instance, the bright red eye of this Red-eyed Vireo is hard to see in the wild because they usually forage quite high up in the trees. In the hand, the red eye is striking and you can also the see the small hook at the end of the vireo’s bill, a feature that distinguishes them from warblers.

A Red-eyed Vireo up close, where it is easy to see the red eye and the hooked bill.

A Red-eyed Vireo up close, where it is easy to see the red eye and the hooked bill.

Note that mist-netting is an unpredictable business and so if you visit the banding station, we can’t guarantee you will see a bird being caught and banded. Cooler mornings can produce over a dozen birds though we catch fewer birds on hot, humid days, probably because the birds are less active. Nevertheless, even on quieter days, several lucky visitors have seen some great birds, including Downy Woodpeckers and a Northern Flicker. Woodpeckers are especially interesting up close, as one can see their unusual toe arrangement with 2 toes pointing forward and 2 pointing backward, unlike the standard arrangement of 3 toes forward and 1 back. This helps woodpeckers climb up tree trunks, as does their stiffened, spiky tail feathers.

The underside of a Flicker showing its distinctive toe arrangement and spiky tail feathers.

The underside of a Flicker showing its distinctive toe arrangement and spiky tail feathers.

In addition to its scientific value, bird banding is a fantastic educational tool, allowing for both adults and children to see birds up close.  By providing this experience, the Delaware Nature Society is helping people better appreciate key bird characteristics like their feathers and differences between species in plumage color and the shape of their feet or beak.  We are also banding nestlings of a variety of species found breeding in our nest boxes, including Eastern Bluebirds, Tree Swallows, and House Wrens, but also Tufted Titmice and Carolina Chickadees. If we are lucky some of these may turn up as adults next year! Dozens of children attending our summer camps have enjoyed checking out the nest boxes for eggs and nestlings, and some have been lucky enough to hold a baby bird!

Happy campers at Ashland Nature Center holding baby Eastern Bluebirds.

Happy campers at Ashland Nature Center holding baby Eastern Bluebirds.

Banding takes place at Ashland Nature Center on Monday and Tuesday 8am -11 am, and at Bucktoe Creek Preserve 8am – 11am, and will run through September. There is no charge to attend the banding, but for non-DNS members visiting Ashland, a trail fee applies.  We hope to see you at the banding station soon!  Songbird migration has started, and you never know what will turn up in the nets.