Avian generations in the making – part 2B: nesting in nature

My last blog looked at birds’ nests in man-made structures and there are plenty of birds who take the opportunity to use such sites. Most birds, however, make their homes out in nature – in shrubs, trees and on the ground. This is a bit of a long blog but I want to share views of different species at work.

There are different types of nests; a few types that we see in North Carolina include:

  • Cavity nests – holes in trees, made by the parents themselves or adopted as a home when birds like the cavities made by others
  • Simple scrapes – these are shallow depressions scratched out on the ground and they may be lined with materials or left to look like the rest of the surrounding ground
  • Cup-shaped nests – these structures are like small bowls and may be lined with materials like those used in nest box nests. They can be made of varied materials – swallows use mud while American robins and other birds use plant materials.
  • Platform nests – these nests are usually quite large and comprise large twigs and small branches
  • Plate nests are a bit similar to platform nests but much smaller and less organized; they may consist simply of a few twigs arranged in a shallow bundle
  • Pendant nests hang from branches.

When birds look for a cavity site, they may seek out a new spot on a tree trunk or investigate already existing cavities. These Eastern bluebirds (Sialia sialis) at Sandy Creek Park were examining one particular hole with interest, but a downy woodpecker was interested as well so there was some rivalry. The female bluebird chose to just sit on a nearby branch while her mate looked at the hole numerous times trying to make a decision.

    

Red-headed woodpeckers (Melanerpes erythrocephalus) excavate larger cavities in tree trunks to raise their broods. They may visit various trees before deciding on a spot.

      

Pileated woodpeckers (Hylatomus pileatus) may use the same holes year after year. They make holes for resting as well as for nesting and often include a “back door” so they can make a quick escape if a snake shows up.

          

Brown-headed nuthatches (Sitta pusilla), like this one at Jordan Lake, can be very industrious in excavating their nest cavities. You can watch them pecking away at the wood of a tree trunk or branch, scattering wood shavings and removing bigger bits of softened wood in their beaks to achieve a hole of the right depth for their babies. (See a short video of one at work here.)

   

I also saw nuthatches making nests on the edges of a farm and near the NC Botanical Garden. The pair working on a nest at the Garden were doing this with a great horned owl on a branch overhead, as well as a red-tailed hawk and crows who were raising a racket. Their presence didn’t bother the little birds; these nuthatches also appeared to have help from a previous year’s youngster willing to help the parents raise the new siblings.

 

 

    

Carolina chickadees (Poecile carolinensis) also dig out small holes in trees and snags.

      

Killdeer (Charadrius vociferous) use scrape nests which may look exactly like the surrounding area; their eggs then blend in really well with the environment and can be difficult to see.

When I first saw this nest suspended from a tree near a bridge, I had no idea which bird had built it. A birding friend had fortunately seen the parent bird fly to the nest – it belonged to a Northern parula like the one shown below (Setophaga americana).

    

I was lucky to see a female orchard oriole (Icterus spurius) collecting nice soft lining materials for its nest this past spring.

         

A red-winged blackbird (Agelaius phoeniceus) was doing the same with cattails – an obviously appropriate source for bird bedding!

       

Mourning doves (Zenaida macroura) and Northern mockingbirds (Mimus polyglottos) make fairly shallow, twiggy nests (“plate nests”). It makes you wonder if eggs ever roll out of them through cracks in the loose, low walls.

   

Many birds make cup nests and spend a good amount of time collecting the materials to produce them. Here you see American robins (Turdus migratorius) gathering grasses – they tend to fill their mouths as much as possible before flying off to the nest-in-the making.

      

Red-eyed vireos (Vireo olivaceus) will also attempt to get several pieces of bark into their beaks before flying back to the home site. The photos here are dark as the bird was deep in shrubs where little light was penetrating.

        

Blue grosbeaks (Passerina caerulea) weave what looks like a cross between a pendant nest and a cup nest; they also add man-made materials such as rags, cellophane, newspaper and bits of plastic.

    

Great blue herons and ospreys are builders of platform nests.The great blue herons (Ardea herodias) carry large twigs and branches to furnish a nest. At Sandy Creek Park they have been using the same tree-top platforms for several years now.

     

Last year, I saw this osprey pair (Pandion haliaetus) build their first nest from scratch; they weren’t enthusiastic about me being in the vicinity and would perch or fly overhead to give me “the evil eye” – sometimes calling to one another to sound the alert that they had spotted me down below.

 

 

This year, they were busy refurbishing the nest – these birds with longer-term mates may use the same nest year after year. Again, they would stop their work to stare me down.

 

The Acadian flycatcher (Empidonax virescens) makes a cup nest that is well-hidden among the leaves of the tree spot it chooses. A friend saw the pair constructing this nest and it was done by the time I visited. It seemed quite a tight fit for mom to sit in while brooding her eggs.

The bird whom I enjoy seeing most during nest construction is the blue-gray gnatcatcher (Polioptila caerulea). These little birds are very active and often don’t sit still for long as they feed in shrubs and trees. When they are busy making a new home though, they take their time to do a good job. First, they locate good locations for the materials they use – leaves, spider web to hold the leaves together and pieces of lichen to cover the outside walls.

      

They affix the lichen carefully to make a really beautiful, compact and elegant little cup. The female then sits in it and moves her body to ensure it gets the right shape and dimensions for her upcoming brooding.

     

The male and female both work hard on the nests and this year I got to see three pairs at work. In two cases, it was lucky I saw them flying to and fro because their nests blended in really well with the tree.

Unlike the cavity and platform nesters, the cup and pendant nesters usually need to build a new nest each year. At the end of the summer, for example, the blue-gray gnatcatcher nest had already deteriorated considerably with the rain and wind, even though it was a fairly calm and dry season.

 

Once the nest is complete, the avian parents brood and feed their babies before fledging and this will be the third part of this series. For now, I leave you with the male and female ospreys as they watch the birdwatcher….

  

Avian generations in the making – part 2A: nesting and man-made construction

Hi folks — today I’d like to share with you some of my observations on the second part of avian reproduction — the process in which birds make a nest and lay eggs. (By the way, if you look up “bird nesting” on the Internet, the search will lead you to a human activity: a shared custody arrangement where children reside in one house and the parents take turns living there with them. In the bird world, some avian parents will actually share a home, such as this very old and enormous sociable weaver nest (Philetairus socius) that I saw in Namibia.)

Females of a few species will deposit their eggs in the nests of another, such as some cuckoos and brown-headed cowbirds (Molothrus ater). Some people dislike cowbirds intensely because of their nest parasitism (the cowbird baby will hatch first and eat all the food or perhaps get rid of the other eggs or babies). I figure that this is how the cowbird evolved – it didn’t make a choice to wipe out other species so I can’t blame or hate the bird for it. But the cowbirds do appear to pick on particular species as involuntary “foster parents” and this may be affecting the success of the other species’ reproduction.

There are two general broad categories of bird nests – those located in or on man-made objects such as nest boxes, atop downspouts, in vehicles, in plant pots and other places and those constructed by birds in trees, shrubs and on the ground (i.e., the natural environment which I will discuss in the next blog so this doesn’t get too long!). When birds make a nest in a “human area”, people will often try to accommodate them, not using the object or vehicle or making the space safer. For example, when American robins (Turdus migratorius) put a nest on one of my downspouts, I covered the rainwater container underneath it so the fledglings wouldn’t drown when they leapt to freedom. (I did it just in time, too!)

Swallows and phoebes will also use human constructions as places to situate their homes. The cliff swallows (Petrochelidon pyrrhonota) gather up mud, making countless trips to wad up small balls of the material to carry back to a place like this pier at Cane Creek Reservoir where they line up their nests in a row.

   

Barn swallows (Hirundo rustica) locate their nests inside, using rafters to place a nest; they may end up sharing space with paper wasps and organ pipe mud dauber wasps (Trypoxylon politum), which doesn’t seem to bother them.

The Eastern phoebe (Sayornis phoebe) may use an inside corner of a patio overhang as a site that is conveniently accessible from outside.

Purple martins (Progne subis) living east of the Rocky Mountains almost exclusively nest in homes provided by people. The hanging gourd nests can be seen in fields but nowadays other types of plastic constructions are also used.

    

In order to attract barn owls (Tyto alba) back to areas where many traditional barns have been razed, people are also placing special boxes in fields with plenty of open space in front of them so that the owls will have a hunting territory adjacent to their front door. Made of heavy plastic, these boxes may be monitored by organized groups in an effort to document their use.

   

At the Mason Farm Biological Reserve, an eagle scout project involved bringing in cranes to attach very large nest boxes to the tops of trees for barred owls (Strix varia) – so far, I have only seen Eastern gray squirrels making use of these nests.

And then there are the nest boxes that people put up to attract Eastern bluebirds (Sialia sialis), brown-headed nuthatches (Sitta pusilla) and screech owls. In my yard, other birds use these boxes, too, including the Carolina chickadees (Poecile carolinensis) such as my one-legged,  banded friend Chantal, Carolina wrens (Thryothorus ludovicianus) who may puzzle about how to get a long twig into the box and house wrens (Troglodytes aedon), who pile up twigs in a rather untidy stack inside the box.

   

   

Chickadees construct lovely mossy nests lined with hair, fur or plant fibers.

      

The nuthatches have nests with bark strips.

    

Sometimes people will intervene when a nest is in danger. A Carolina wren put her nest into a boat at Cane Creek Reservoir that was rented out to people and keeping the nest there was not a good option as she would be missing her nest for hours when the boat was gone. The land manager was so kind as to relocate the nest into a tree right in front of the boat’s resting place; unfortunately, inclement weather caused the nest to dislodge that evening.

   

Another danger may also threaten the birds and their nests – predators. A friend and I found it unusual to see a tree swallow (Tachycineta bicolor) putting a nest in a bluebird box on the edges of a farm. Several days later, we saw a black rat snake (Pantherophis obsoletus) peering out of the box and the swallows were nowhere to be seen.

   

If you can manage to mount your boxes on poles rather than trees, put both squirrel and raccoon baffles on them and also place them away from overhanging branches, they should stay relatively safe from the squirrels, snakes and raccoons. Next up: birds’ nests with no human connections.

 

 

Flying rays of sunshine, spirits on the wing – part 2

Cabbage white butterfly DK7A2287© Maria de Bruyn resWhen a butterfly like the cabbage white (Pieris rapae) alights on a flower or leaf, we sometimes have a little time to see them more clearly and appreciate their beauty; capturing a photo for leisurely viewing gives us the chance to focus on details. And those details are important if we want to determine their correct scientific names since entomologists have differentiated many species and sub-species, sometimes on the basis of factors such as the shape of their spots.

One butterfly pair that can be puzzling are the silvery checkerspot (Chlosyne nycteis, top), with a small white center to one of its spots in the lower row, and the pearl crescent (Phyciodes tharos), which was abundant this year.

silvery checkerspot DK7A1405© Maria de Bruyn res

pearl crescent DK7A1469© Maria de Bruyn res pearl crescent DK7A4689© Maria de Bruyn res

The Eastern comma (Polygonia comma) and question mark (Polygonia interrogationis) look really similar, too. Perhaps the difference in their distinguishing underside marking is really apparent to proofreaders.

Eastern comma DK7A5636© Maria de Bruyn resQuestion mark DK7A3181© Maria de Bruyn res

The easiest way to distinguish the endangered monarch (Danaus plexippus) and the viceroy (Limenitis archippus) is that the viceroy has a black stripe running horizontally across its lower wings.

monarch DK7A7941© Maria de Bruyn res

viceroy DK7A5128© Maria de Bruyn res

Eastern tiger swallowtail DK7A2096© Maria de Bruyn res

The swallowtails are always a favorite, including the Eastern tiger swallowtail (Papilio glaucus) with differently colored males (yellow) and females (yellow and also blue).

 

Eastern tiger swallowtail DK7A7768© Maria de Bruyn res Eastern tiger swallowtail DK7A0256© Maria de Bruyn res

Zebra swallowtail DK7A0046© Maria de Bruyn res

The zebra swallowtail (Protographium marcellus) really catches your eye as it flutters about, while the pipevine swallowtail (Battus philenor) is a little more subdued.

 

Pipevine swallowtail DK7A9681© Maria de Bruyn res Pipevine swallowtail DK7A9691© Maria de Bruyn

The red spotted purples (Limenitis arthemis) come in different variations; this one enjoyed the hummingbird nectar this summer.

Red-spotted purple DK7A0518© Maria de Bruyn res Red-spotted purple DK7A0998© Maria de Bruyn res

Another new butterfly for me this year was the great spangled fritillary (Speyeria cybele), which I enjoyed seeing as they enjoyed common milkweed (Asclepias syriaca) at the Horton Grove Nature Reserve.

great spangled fritillary DK7A5377© Maria de Bruyn res Great spangled fritillary DK7A5052© Maria de Bruyn res

Hackberry emperor DK7A6150© Maria de Bruyn resThe hackberry emperor (Asterocampa celtis) turned up at Jordan Lake, while the common buckeye (Junonia coenia) – whose beauty is anything but common! – was in my yard and various nature reserves. I also observed a pair getting ready to propagate the next generation.

 

 

common buckeye DK7A1181© Maria de Bruyn common buckeye DK7A8729© Maria de Bruyn res common buckeye IMG_9470© Maria de Bruyn res common buckeye IMG_9538© Maria de Bruyn res

Some of the tinier butterflies are delicate beauties, like the Summer azure (Celastrina neglecta), the gray hairstreak – which can look brown (Strymon melinus), the Eastern tailed-blue (Cupido comyntas) and the Carolina satyr (Hermeuptychia sosybius).

Summer azure DK7A5424© Maria de BruynGray hairstreak DK7A4495© Maria de Bruyn

Eastern tailed-blue DK7A1141© Maria de Bruyn resCarolina Satyr DK7A5279 © Maria de Bruyn res2

To end, here are two more beauties that I had the privilege to see this year. I hope  seeing these butterflies and those in my previous blog brightened your day, especially if you have been dealing with sorrow as I have while this year approaches its end.

Southern pearly eye DK7A9953© Maria de Bruyn resNorthern pearly-eye DK7A7752©Maria de Bruyn res

Southern pearly eye (Lethe portlandia) and Northern pearly-eye (Enodia anthedon)

 

Flying rays of sunshine, spirits on the wing – part 1

Fiery and dun skippers IMG_7262© Maria de Bruyn resIt is now early December and late autumn in the Northern hemisphere, so why a blog about butterflies? When I was writing this on the last day of November, I had still seen a few of these beauties a couple days previously, and in the Southern hemisphere it is late spring, so it seems fine as a topic for a nature blog. Also, three weeks ago, my mother passed away, while in two weeks the anniversary of my father’s death comes again — I like to think of butterflies as nature’s emissaries for spirits on the wing. They allow me to think of my parents in somewhat lighter terms than the sadness that predominated during their dying processes. Because there are so many butterflies to highlight, this will be a two-part blog.

This past spring, summer and fall gifted me with a large variety of butterflies – a boon compared to last year when there seemed to be a dearth of them. I had some new butterflies to my garden, like the tawny emperor (Asterocampa clyton clyton), which I also saw at the Mason Farm Biological Reserve when one landed on my arm.

Tawny emperor DK7A2536© Maria de Bruyn resTawny emperor IMG_4926© Maria de Bruyn (2)

juniper hairstreak DK7A1677© Maria de BruynThe juniper hairstreak (Callophrys gryneus) was another new visitor that at first made me think it was covered in pollen.

A second-time visitor to my yard was the American snout (Libytheana carinenta), which looks quite distinctive with the long protrusion from its face.

American snout butterfly IMG_0257© Maria de Bruyn res

It was a good year for the little skipper butterflies, of which there are many. Quite a few look similar to one another and pose difficulties in identification; fortunately, BugGuide helps me figure out which ones I have been seeing.

 

Common checkered skipper DK7A8473©Maria de BruynCommon checkered skipper DK7A8483©Maria de Bruyn

Common checkered skipper (Pyrgus communis)

silver-spotted skipper IMG_0885© Maria de Bruyn Fiery skipper DK7A3463© Maria de Bruyn

Silver-spotted skipper (Epargyreus clarus) & Fiery skipper (Hylephila phyleus)

Zabulon skipper female DK7A8091© Maria de Bruyn Zabulon skipper DK7A2945© Maria de Bruyn res

Zabulon skipper (Poanes zabulon), female on the left and male on the right

sachem skipper DK7A6355© Maria de BruynSachem skipper male DK7A7657©Maria de Bruyn res Sachem skipper DK7A1271© Maria de Bruyn bg

The Sachem skipper (Atalopedes campestris) also illustrates how males (top) and females can differ.

A few skippers were new for me this year, like the little glassywing skipper (Pompeius verna) and the somewhat drabber dun skipper (Euphyes vestris) and Ocola skipper (Panoquina ocola).

Little glassywing skipper DK7A2843© Maria de Bruyn  Dun skipper DK7A3364© Maria de BruynOcola skipper IMG_4247©Maria de Bruyn

Even though dark in color, the Horace’s duskywing (Erynnis horatius) and the Juvenal’s duskywing (Erynnis juvenalis) have beautiful dorsal patterns.

Horace's duskywing DK7A3695© Maria de Bruyn

Juvenal's duskywing DK7A9907© Maria de Bruyn res

It’s always fascinating to see how different the butterflies’ color patterns can be on the upper and undersides of their wings, as shown here by the American lady (Vanessa virginiensis).

American Lady DK7A2242© Maria de Bruyn res American Lady DK7A2292© Maria de Bruyn res

The red admiral (Vanessa atalanta) is a gorgeous butterfly; a somewhat tattered individual rode along on me and my camera for a while at Mason Farm.

Red Admiral DK7A6667©Maria de Bruyn (2) res

red admiral IMG_4769© Maria de Bruyn red admiral IMG_4767© Maria de Bruyn res

A group that can sometimes be challenging to identify are the sulphurs. Distinguishing the sleepy orange (Abaeis nicippe, top) and the orange sulphur (Colias eurytheme) is no easy task. Both are quite lovely and a delight in flight when they reveal their brightly colored dorsal pattern.

Sleepy orange DK7A8367© Maria de Bruyn Sleepy orange DK7A8263© Maria de Bruyn

Orange sulphur DK7A0410© Maria de Bruyn resOrange sulphur DK7A0476© Maria de Bruyn res

Cloudless sulphur DK7A2774© Maria de Bruyn res

The larger yellow butterflies like the cloudless sulphur (Phoebis sennae) are great to see, especially when they frequent the brightly colored blooms such as the red cardinal flower (Lobelia cardinalis).

cloudless sulphur DK7A8466©Maria de Bruyn resCloudless sulphur DK7A0063© Maria de Bruyn res

Clouded sulphur DK7A0269© Maria de Bruyn

The clouded sulphur (Colias philodice) may be a bit harder to see when it feeds on clover in the grass.

Stay tuned for more butterflies to admire in part 2 of this blog!

 

Motherhood in the wild

yellow-bellied slider IMG_3703© Maria de Bruyn res After watching the baby herons today at the Sandy Creek Park rookery (blog coming on that!!), I walked down a path taking photos of plants and flowers, ending in a spot where I wanted to check on what had happened to a moth cocoon. To my surprise and delight, when I glanced to the side, I saw a yellow-bellied slider (I think, Trachemys scripta scripta) in the process of laying her eggs.

yellow-bellied slider MG_3704© Maria de BruynI didn’t want to get too close but was really curious as well since this would be the first time I had seen a turtle laying eggs. So I inched a bit closer and witnessed her last egg dropping down into the nest. Happy turtle and happy me!

She immediately began covering it by pushing dampened earth over it with her hind legs and feet.

yellow-bellied slider IMG_3706© Maria de Bruyn res yellow-bellied slider DK7A4271© Maria de BruynMother turtle kept an eye on me during this process, pausing if I moved too close.

yellow-bellied slider DK7A4273© Maria de Bruyn resAt one point, I continued along the path to give her a little privacy and came upon another turtle – perhaps also looking for a nesting site?

Yellow-bellied slider DK7A4294© Maria de Bruyn res yellow-bellied slider DK7A4296© Maria de Bruyn res

This turtle’s eggs will now incubate for a period of two to three months. When the babies hatch, they will likely stay near the nest during the winter, eating insects, spiders, carrion – an almost exclusively carnivorous diet. If left alone by humans and predators, they can grow up to live as long as 30 years in the wild.yellow-bellied slider DK7A4270© Maria de Bruyn res yellow-bellied slider DK7A4439© Maria de Bruyn res

yellow-belllied slider DK7A4286© Maria de Bruyn resI left mom to the task of covering the site and returned about 20 minutes later. She was nowhere in sight and it was only because I had seen her on the nest that I could tell where she had laid the eggs. I hope I remember the site so that I can return in a couple months and perhaps be lucky enough to see the babies emerge.