AvianActs: Birds Nesting in the 'patch'

Optical and thermal images of robin on her nest

Nest Sanitation: The housekeeping of the nest was done by the male, removing any droppings from the nest. He came to the nest periodically and used his beak to clean the nest while perched on the rim. Once the chicks were a few days old they defecated over the rim, and he caught the fecal sac in mid-air (Day 10 photo) - quite a feat with coordination in ejecting and catching!! The empty nests were clean and there were no signs of any droppings or mites in the nest cup even after a month or two.

The female robin on a nest always flew away when someone approached the nest. She then watched from a nearby perch and chirped mildly protesting the intrusion. This is the behavior observed in general; robins are gentle birds, but there can be exceptions. Erica Backmann, who lives in Connecticut, reported an American Robin nesting in her yard with the male dive-bombing any person that came near the nest. She had to use an umbrella for protection as she walked towards her car. When I visited Erica, I was also attacked by this male robin; he was not discriminating. Others have reported American Robins reusing an old nest, a practice not observed in my 'patch'. We learned it is not fair to generalize the behavior of an avian species based on that of a small number of individuals.

 

Carolina Wren

 

This small bird, weighing less than an ounce, is one of the most vocal species here. The rufous back and lighter belly blend in well with dry shrubs and leaves. Its presence is most easily detected by loud vigorous singing heard all year round. Males and females look alike but can be differentiated when seen vocalizing as only the male sings. His repertoire may have over 20 song types comprising trills and rattles, each type repeated a few times. Nests are often close to human habitation, and they attempt two to three broods each year.

Carolina Wrens are regular visitors in the Home 'patch' all year, but it was only in 2023 that I had an opportunity to watch them nesting. On June 24^th I heard several birds chattering in the woods. There was a family of Carolina Wrens hopping on a brush pile, adults and some recently fledged young with their gape flanges clearly visible. Next day, two adults were busily collecting nesting material from a planting bed and flying towards my house. They appeared to be preparing for another brood while some fledglings were still hanging around the adults. The nest location turned out to be under the lid of the 100-gallon propane

tank next to the deck stairs. The lid was tightly fitted on the tank and the birds were using an opening in the sidewall through which gas lines enter and exit. On June 30^th, six days after the nest building began, I lifted the lid with some difficulty. As a courtesy to the mother bird, I banged on the tank first hoping that she, if on the nest, would fly away. All was quiet so I struggled a bit with the lid to raise it and almost fell backwards when a bird flew past my face. Carolina Wrens are reported to be 'tight sitters' on the nest, i.e. the female does not leave the nest easily, and this one certainly behaved as documented by others.

The nest was a loose collection of twigs, and there were five eggs in it - four lovely pink colored ones and a single larger speckled egg. Brown-headed Cowbird, a parasite brooder, had managed to find the nest in this well concealed location and laid an egg for the Carolina Wren to incubate.

 

It was best to let the mother bird sit on her eggs undisturbed. For the next two weeks I watched the male perched on a small tree nearby singing away. When a neighbor's cat came for a stroll along the planting bed, he was agitated and gave alarm calls - long chattering notes. On July 14^th I saw both adults flying towards the nest with food in their beaks. It was time to check the nest again. I waited until I saw both adults on a nearby tree before lifting the lid. All eggs had hatched, but it was difficult to count the number of naked chicks without touching them, which I was not inclined to do.

I continued to watch the adults bringing food to the nest for the next four days. Then I was away from home for ten days. When I returned the male was singing in the woods but not seen. Under the lid was a mess of twigs and grass spread all over the tank top as if the little chicks wanted to spread out. I wondered if any of the chicks, Carolina Wrens and Brown-headed Cowbirds, had fledged successfully.

CarolinaWrens build nests in trees and shrubs but also select man-made objects. Some nest site locations listed in a 1948 study include shoes, mailboxes, old coat pockets and under covers of house propane tanks. My propane tank, installed to service a backup generator during power outages, has now been used as a nest box. I cleaned up the mess in case the birds return to use it again.

Chipping Sparrow

 

Chipping Sparrow, one of the smaller sparrows, has a rufous crown and an unstreaked breast. These sparrows arrive here in the beginning of April, announcing their presence with a series of loud trills repeated at intervals of about 10 seconds. Nest building begins in the middle of May - four to six weeks after arrival. Male and female look alike, but only the male sings in the breeding season, starting at dawn and continuing throughout the day. There are typically two broods in a season.

I have found many Chipping Sparrow nests in the yard over the years. Their favorite shrubs are sky pencil holly (Ilex crenata) in my front yard. I could see Chipping Sparrows going in and out of one of these shrubs from my office window. Finding the nest in the shrub was not easy as this small delicate object was neatly tucked away among the inner branches. They have also built nests in barberry (Berberis thunbergii) bushes, wisteria (Wisteria frutescens) vines and once in a 'Thundercloud' flowering plum (Prunus cerasifera) tree. Except for the nest in the plum tree, all other nests were just two to three feet from the ground.

I generally refrain from going near the nest site except once or twice when my curiosity takes over. When the female is incubating, the male sings from a perch higher up in a tree or on the roof. When I go near the nest the female flies away, but not too far, and chirps in protest. Once the eggs have hatched, both male and female bring food, making frequent trips between the tall trees in the woods and the nest. From the movements of the adults, I can guess if the eggs have hatched successfully.

 

The eggs, three to four in a clutch, are blue and lightly speckled. The nests are somewhat exposed and subject to parasite brooding by Brown-headed Cowbirds and predation. In July of 2007 and again in 2015, I watched a Chipping Sparrow bringing food to a cowbird chick. The chick was calling incessantly as it followed the sparrow. It was about three times the size of the sparrow who had to jump up from the ground to reach its open bill. It was touching to see how the instinct of parental care and protection is embedded in these creatures.

In 2023 two pairs of Chipping Sparrows nested in the yard at about the same time, one in the front yard and one in the backyard in a vine under the deck. As I looked through my window, I saw a Chipping Sparrow with nesting material in its beak flying towards the house and disappearing under the deck. Another one was on the dogwood (Cornus florida) tree about thirty feet from the deck. I located the nest, about three feet from the ground, while it was under construction in the hydrangea vine (Hydrangea anomala) climbing on the support pillars of the deck. The nest was completed in three days. On the fourth day, the Chipping Sparrow brought some white fluffy stuff to the nest. The following day I did not see these birds.

In the afternoon of May 7^th, five days after the nest was initiated, there were two light blue eggs in the nest. A smartphone camera with a remote shutter, positioned a few inches above the nest with our team member Mark holding the branches apart, worked well for capturing an image. Next afternoon, we repeated the nest inspection at the same time of the day. To our surprise, there were four eggs, two blue and two larger speckled eggs. How did a Brown-headed Cowbird manage to lay two eggs in this nest in a twenty-four period? This had to be the work of two cowbirds as one bird lays only one egg per day. Did the Chipping Sparrow also lay another egg that day which the cowbirds removed?

The following day, there were five eggs in the nest, three of the Chipping Sparrow, and two of cowbirds. From then on, the female Chipping Sparrow was on the nest while the male perched on the dogwood tree delivered his trilled notes. On May 25^th, 17 days after the incubation process began, I checked the nest again. There were no eggs in the nest, and the chicks were a few days old as their skins were covered with small down feathers. I could not tell exactly how many chicks were in the nest - at least four bills were visible. Two large mouths opened expecting food delivery from the camera positioned above.

 

The vine had grown more, and the nest was now completely hidden behind dense foliage. I did not inspect the nest again but watched the Chipping Sparrows bringing food. They used the dogwood tree as an intermediate stop between the source of caterpillars on the tall trees and the nest. They were finding caterpillars, juicy green, flat brown, and knobby brown with a yellow tail, in less than three minutes. Then it was time to rest on the dogwood tree for a minute or two before the delivery. By May 29^th they were bringing two to three caterpillars at a time keeping up with the demands of the cowbird chicks.

 

On the afternoon of May 31^st, while I was watering plants, I saw a small chick in the planting bed. It was hopping awkwardly in between the shrubs. Then I heard the chip call of the Chipping Sparrows. The two of them were on the lower branches of trees at the edge of the woods, signaling to the chick to move towards the woods. I had enough time to get the camera before the chick disappeared in the woods. I checked the nest and found only one large chick remaining, clearly that of a cowbird. There was no sign of Chipping Sparrow chicks dead or alive. Three hours later the second chick fledged and landed near a boxwood shrub in the planting bed visible through my kitchen window. The Chipping Sparrows were nearby and kept calling but the chick hid under the shrub and did not venture out. The adults were focused on helping the fledgling they raised at the cost of losing their own. Next morning at 7AM, the second chick was still in the same shrub, and the sparrows were delivering green caterpillars. It took some more coaxing to get the chick to move away. I did not see this family with adopted chicks together again.

 

While this drama was taking place in the backyard, another pair of Chipping Sparrows had a nest in a sky pencil holly in the front yard. The male would perch on the roof top and sing nonstop every time I stepped out on the driveway. When I examined the nest on May 31^st, the day the cowbird chicks fledged in the backyard, this nest had one Chipping Sparrow egg, one cowbird egg and one recently hatched chick. On the next inspection, five days later, there were only chicks in the nest. I checked the nest again when the adults stopped bringing food and found it unoccupied. In the following two weeks I saw a Chipping Sparrow chick and a cowbird chick following a Chipping Sparrow in the woods.

 

Every year 20 to 30 Chipping Sparrows come to feed in the grassy areas of my backyard from September through early November, flocking before migrating south. There are juveniles, identified by a brown crown and thin dark streaks on the body, mixed with adults having rufous crowns. The presence of juveniles confirmed that some nests have been successful. A healthy population of Chipping Sparrows consistently returns each spring.

 

House Finch

A House Finch is slightly smaller than a House Sparrow and is dichromatic. The male has red coloration on the crown, throat, upper back, and rump. The female is of dull tan-brown color with heavy streaking on the body. This species can survive in diverse habitats and is now widely distributed in most parts of North America. As the name implies, they often build nests on buildings and other man-made objects like lamps and planters. Nesting begins in late March or early April. It is one of the earliest songbird species to begin nesting and may have two to three broods in a season.

In the spring of 2020, a pair of House Finches chose to build a nest on top of a gutter spout near my front door. The female collected nesting material from various planting beds around the house, and the male followed her closely. Ten days after the nest building began, the female House Finch was sitting on the nest. A few days later the nest was left unattended, perhaps robbed by European Starlings or House Sparrows that were often on the roof of the house. I removed the nest debris from the gutter at the end of the season.

At about the same time in early spring of 2021, House Finches began building a nest at the same spot on the gutter. A couple of weeks later, the female was observed sitting on the nest at around 7 AM each morning for an hour or two. After four days she was on the nest all day long - incubation had begun. The male was perched on a tree next to the driveway and sang his warbled song ending with a downward slurred note. I learned more about his role when I walked out to photograph the female on the nest. His song ended abruptly, and he chirped twice; immediately the female flew away from the nest. I stayed fifty feet from the nest but was still considered a threat to his dear one.

Lawrence Slomer had introduced us to the borescope, an instrument designed to inspect hard to reach places, for inspecting nests. We acquired an Oiiwak Dual Lens Endoscope. Tying the 16 foot cable to a long rod and bending its end downwards, we raised it high enough to view the nest on the monitor and capture an image when the female was away from the nest. There were four eggs in the nest. A week later there was only one egg in the nest. The female continued to incubate for two more days and then abandoned it. All eggs were gone.

The same sequence was repeated in 2022. Nest building by the House Finches was initiated at the end of March, but they waited for a month to complete the nest, adding more material and rearranging the twigs. I viewed the nest from a safe distance at around 7 AM each morning - this being the time she sits on the nest to lay eggs, one each day. Egg laying began on April 26^th. When I inspected the nest with the borescope on April 30^th, there were five eggs in the nest. A Brown-headed Cowbird had laid an egg in the nest and the House Finch was incubating it along with four of her own. The next inspection on May 16^th, two weeks later, revealed four chicks and one unhatched House Finch egg. Four days passed by, and then the House Finches were no longer around. The nest was empty - robbed again as in the previous year.

The resilient House Finches made one more attempt to use this nest site that season. In the middle of June, a pair was in the front yard quickly refurbishing the old nest. Three eggs were laid, but unfortunately on the fourth day the nest was on the ground and the eggs were missing.

I cleaned the nest area which is in full view of many birds in flight and also from the roof top. There were no attempts to use this site in 2023. Maybe the House Finches found a more secure place for nesting.

 

Northern Cardinal

The male Northern Cardinal has a striking brilliant red plumage. Throughout the breeding season his loud whistled songs are heard near forest edges and often even in city parks and gardens. The female has subdued tan coloration with a tinge of red on the wing and tail feathers. Her bright orange triangular bill and reddish crest matches that of the male. She also sings when nesting. There are typically two broods in a season, the male actively guarding his territory while the female builds the nest and incubates. Both parents feed the nestlings, while the male also performs guard duty throughout.

In previous years, I had seen fledglings being attended to by the parents but did not find any nests. In 2023, I luckily located two nests, one in May and the second one in August, likely of the same pair. The first nest was in a burning bush (Euonymus alatus) next to my neighbor's house. As the female was collecting nesting material and taking it to the nest site, the male followed her closely. I could guess the progress on the nest only by watching the movement of the adults. When the female was incubating, the male stood guard and sang from dawn to dusk perched on different trees in the area. After a couple of weeks, both parents were making frequent trips to the nest, bringing food to the chicks. Then on May 13^th, when I went out to water some shrubs, I saw the cardinals calling and moving between the nesting site and the woods. I saw some movement on a small shrub in the planting bed and spotted a fledgling as it hopped awkwardly from one branch to another. I dropped the watering can and ran inside to get a camera. The chick was still on the same plant when I returned. Satisfied with a few nice photographs I moved away and watched the parents urging this chick and another one I could not see to move towards the woods. They succeeded in getting the chicks to a safe place, and I did not see them again. For the next week to ten days the male cardinal was often at the edge of the woods, moving from one tree to another. When the neighbor's cat came for a stroll, he gave chip alarm calls, keeping the cat in sight until she left the area.

In the beginning of August, I was cutting some black cherry (Prunus serotina) tree branches that were extending horizontally and getting tangled with the dogwood tree. After snipping a few I noticed a nest on the next branch I was about to cut. Not knowing for sure if this was a nest in use or an abandoned one, I left it alone and stopped trimming. Next day, looking through my window, I saw a female cardinal moving in that area. Just by sheer chance, through a small gap in the leaves I saw her sitting in the nest. Now I could follow the activity on the nest from inside my house, 50 feet away. When on the nest she was well camouflaged except for her orange beak shining through the leaves as she moved. To check the status of the nest, I got help from our team member Mark who volunteered to climb a ladder and take pictures with a smartphone camera. There were two eggs in the nest. After an interval of two weeks, we checked the nest again, and there were two chicks with beaks wide open, expecting to receive food. From then on, I watched the adults through my window as they went towards the nest to feed the chicks. One morning 10 to 12 days after the eggs hatched, there was a high level of activity with the adult cardinals going back and forth to the nest area, and then all was quiet. For another week, the male cardinal was in the woods and sounding alerts when the cat came by, so I assume the chicks fledged successfully. He stopped singing altogether once the nest was empty and made chip calls only.

There were a couple of heavy rainstorms with high winds during the nesting period. The nest was anchored so securely to the branch with a thicker twig (indicated by an arrow in the photograph) that it could withstand severe weather - a noteworthy engineering feat by the female cardinal. The empty nest after fledging was intact and clean.

 

 

 

Red-tailed Hawk