Mercury Poisoning in a Young Saltmarsh Sparrow

Saltmarsh Sparrow / Photo by Wolfgang Wander

Most of us are familiar with the hazards posed by mercury. In the compound known as methylmercury, it becomes a potent neurotoxin, for both humans and wildlife. When infants are exposed in utero, methylmercury causes a variety of developmental problems. Environmental mercury comes primarily from industrial sources, such as waste incineration and the burning of fossil fuels for energy. Burning coal for electricity is a particularly strong contributor. Mercury is aerosolized by these processes and then enters waterways via precipitation. Aquatic invertebrates and fish consume mercury through their diets. It is for this reason that pregnant women are advised to avoid fish, some of which store significant levels of methylmercury in their tissues.

Methylmercury has already been documented in multiple bird species, with particularly high concentrations in Wood Thrushes. Some birds such as raptors and kingfishers have fish as a mainstay of their diets. Songbirds consume mercury by eating invertebrates that spend the early stages of their life in the water (such as mosquitoes, dragonflies, and caddisflies) or by eating spiders that prey on those aquatic invertebrates. Mercury is associated with behavioral changes in songbirds and may skew sex ratios. Like in humans, mercury affects learning and memory in songbirds. It also hampers birds' ability to learn and sing songs.

A new study by Sheila Scoville and Oksana Lane adds to the evidence for mercury's harmful effects in songbirds. When a fledgling Saltmarsh Sparrow (Ammodramus caudacutus) was accidentally killed at a study site on Long Island, it was collected and analyzed for mercury poisoning. Feathers were collected and sent to the Biodiversity Research Institute to test for mercury exposure, and the sparrow's brain was analyzed at the Eastern Virginia Medical School. The fledgling showed some exposure to mercury, though not at the levels measured in adults at that study site (which overall were very high).

Based on feather samples taken from adult birds at the study site, it can be inferred that this fledgling's mother had high exposure to mercury at the time that she laid her eggs. This is analogous to in utero exposure in humans. In humans, in utero exposure can lead to brain abnormalities like Minamata Disease. This fledgling Saltmarsh Sparrow showed abnormalities in its cerebellum that would have similar effects on motor control and coordination. Birds with these sorts of defects would have trouble recognizing and escaping danger, thus making them more susceptible to predation and accidental deaths.

While this fledgling Saltmarsh Sparrow is only one data point, the findings have disturbing implications. Since mercury levels among adult birds were so high, many other young Saltmarsh Sparrows are presumably exposed to mercury at the time of egg formation. We cannot know how many of them have brain abnormalities like the one documented in this study, but it seems safe to assume that the problem is widespread.

Even without human interference, Saltmarsh Sparrows lead a precarious existence. At any time during the breeding season, their nests may be flooded by particularly high tides or destroyed by violent storms. Their breeding range is restricted to a narrow strip of saltmarshes along the Atlantic Coast of the United States. Their habitat is constantly under pressure from human encroachment, as more and more coastal areas are developed as beach resorts. Oil and chemical spills further degrade their remaining habitat. There is an additional threat from sea level rise due to climate change and subsidence. For these reasons, BirdLife rates the Saltmarsh Sparrow as a vulnerable species. Now we know that in addition to all these other problems, the species also faces a threat from ingestion of mercury.

The harm caused by mercury is not something conservationists can easily remedy. Shifting away from coal as a source of electricity would at least reduce the amount of mercury entering our waterways. What we can and should do is protect and maintain as much remaining saltmarsh as possible so that the sparrows that survive to adulthood will have enough habitat for breeding.

Thanks to Peter Doherty for alerting me to this study.

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Scoville, S., & Lane, O. (2013). Cerebellar Abnormalities Typical of Methylmercury Poisoning in a Fledged Saltmarsh Sparrow, Ammodramus caudacutus Bulletin of Environmental Contamination and Toxicology, 90 (5), 616-620 DOI: 10.1007/s00128-013-0974-y

Fox Sparrow

Before the snow's arrival yesterday, I walked through Rutgers Gardens. I started out by walking through the ornamental conifers to see if anything unusual was hanging around them. There was very little activity, so I moved on. My impression is that there are not a lot of seed cones on them, so winter finches there are probably unlikely.

From there I walked through Helyar Woods. There were quite a lot of trees down in the wake of Hurricane Sandy. A lot of trails were blocked by fallen trees, especially the trails close to the lake, which are blocked in multiple places.

There was some bird activity in the woods, but the best birding was in the meadow that is across Route 1 from Sears. One of the first birds I heard there was a Winter Wren; I would see another one further out in the meadow. There were a lot of White-throated Sparrows around, and then a Fox Sparrow popped up and perched on top of a multiflora rose tangle. That made it my 221st bird species in Middlesex County and my 195th in the county for the year. I saw three Fox Sparrows in all, one of which was singing, including the one in the photograph above. Other birds in the meadow included Golden-crowned Kinglets, Yellow-rumped Warblers, and a Hermit Thrush (also a county year bird).

On a sad note, there was a dead Cooper's Hawk near the bamboo forest. From the plumage and size, I would say that it was an adult female. The cause of death was not visibly obvious, but the location suggests an auto collision.

White-throated Sparrows in Autumn

White-throated Sparrows (Zonotrichia albicollis) breed in northern forests and migrate south to the eastern and southern United States during the fall. In New Jersey, they stay through the winter, often in large flocks. I usually hear White-throated Sparrows before I see them. They call constantly to each other and kick up leaves with their feet to uncover food. Even though they are so noisy, it can be hard to see them under shrubs and thick tangles of branches.

I took all of these photos in my backyard over the past few days. There have been at least six, maybe more, hanging around. The challenge with photographing them is to catch them when they hop onto an exposed perch where they might only sit for a few second before going back down into the fallen leaves.

Sparrows on the Move

Recent cold fronts have pushed more sparrows into the area. Song Sparrows, like the one above, are present year-round, but in the last couple weeks, I have been seeing a lot more of them than usual. Some of that is probably post-breeding dispersal (yesterday I saw one that looked very young!), but migrants are surely part of the influx.

Yesterday I also saw my first White-throated Sparrows of the fall. I thought I had heard some calling (with their soft chip notes) once or twice before, but I had not gotten a visual confirmation.

Sparrows at Lord Stirling Park

Yesterday, I visited Lord Stirling Park in Somerset County in the hopes of finding some sparrows. The park has a mix of woodland and meadow habitats in addition to the swamp that the area is known for. I have had some luck with sparrows there in past autumns, such as the Lincoln's Sparrow I found in 2007.

The morning started out slow, with some flocks of White-throated Sparrows and Dark-eyed Juncos but not much else. As I continued around the trails, I found a few Eastern Bluebirds. One of the bluebirds flew up to a nesting box, clung to the front of the box, and stuck its head through the entrance hole as if it were feeding a nestling or checking out the cavity. Soon it was joined by a second bluebird, and both birds perched on top of the box. I am not sure exactly what it was doing. It seems too late for nestlings, so perhaps it found a source of invertebrates, maybe a spider web or a mass of insects seeking a sheltered place to spend the winter.

When I got to the farthest meadow, near the west observation platform, I finally found some bigger sparrow flocks, though most of the birds were either White-throated Sparrows or Dark-eyed Juncos. A few flocks included Swamp Sparrows and Song Sparrows. As I rounded the south end of the main pond on my way back to the parking lot, I enjoyed a nice view of a Fox Sparrow, a highlight on almost any birding trip.

Sparrows in Hotter Climates Have Larger Bills

On a hot day, you need to do whatever you can to keep cool, especially if you have to be out in the sun. Humans, at least, have the ability to sweat: the skin produces moisture, and the heat makes it evaporate, cooling the skin. (At least that is how it usually works; if the humidity is sufficiently high, that moisture will not evaporate easily.) Birds cannot sweat, so they have to find other ways to cool down. One way is by panting: they open their bills to let heat escape through their mouths.

Song Sparrow / Cephas

For some birds, the bill itself presents a way to regulate temperature. That seems to be the case for coastal sparrows:

Scientists at the Smithsonian Migratory Bird Center at the Smithsonian's Conservation Biology Institute and colleagues examined five species of sparrow that inhabit salt marshes on the East, West and Gulf coasts of North America. While these marshes are very similar in makeup and structure, the main difference among them is summer temperatures. Focusing on 10 species and subspecies of tidal salt marsh sparrow, the team measured 1,380 specimens and found that the variation in the sparrows' bill size was strongly related to the variation in the daily high summer temperatures of their salt marsh breeding habitats—the higher the average summer temperature, the larger the bill. Birds pump blood into tissue inside the bill at high temperatures and the body's heat is released into the air. Because larger bills have a greater surface area than smaller bills, they serve as more effective thermoregulatory organs under hot conditions. On average, the study found the bills of sparrows in marshes with high summer temperatures to be up to 90 percent larger than those of the same species in cooler marshes....

The scientific theory known as Allen's Rule states that warm-blooded species from colder climates usually have shorter limbs or appendages than the equivalent animals from warmer climates. The team's new findings are a new example of Allen's Rule that confirms the importance of physiological constraints on the evolution of vertebrate morphologies, even in bird bills.

The full paper from Ecography is online via the Smithsonian site (pdf) if you want to read it. I was surprised that the press release did not mention which bird species were involved in the study since that is one of the first things I wanted to know. From the paper, I can see that they used four subspecies of Song Sparrow (Melospiza melodia atlantica, M. m. pusillula, M. m. samuelis, and M. m. maxillaries), two subspecies of Savannah Sparrow (Passerculus sandwichensis rostratus and P. s. beldingi), one subspecies of Nelson's Sparrow (Ammodramus nelson subvirgatus), Saltmarsh Sparrow (Ammodramus caudacutus), and two subspecies of Seaside Sparrow (Ammodramus maritmus maritimus and A. m. fisheri). Some breed along the Atlantic Coast, some along the Gulf Coast, and others on the Pacific Coast.

Grasshopper Sparrow

When I visited my patch yesterday, I knew there had been steady migration over New Jersey during the night, so I was hoping to see some warblers or other new arrivals. The southerly air flow over the state has brought us unseasonably hot temperatures but also several successive nights of heavy migration. As it turns out, the warblers I saw the previous day seemed to have moved on since there were fewer singing Yellow Warblers and a lot fewer Yellow-rumped Warblers. The orioles and catbirds were still around, though.

Shortly after I started my usual route I saw a small bird fly out of a small wetland area and land at the edge of the nearby ballfield, where it joined some Chipping Sparrows and started foraging. As I tracked it in flight, I saw that it had a short tail and looked yellowish, so I was expecting a Savannah Sparrow, a species I have been seeing at that park almost every day. Instead, when I focused my binoculars on it, I saw this guy:

A Grasshopper Sparrow! This was the first I had seen in Middlesex County, so I couldn't believe my eyes when I recognized it. Unlike with a few other sightings, this time I remembered to take photos. Even if they are not great, they show an identifiable bird.

Grasshopper Sparrows are locally common in areas with lots of grassland habitat. That habitat is scarce in Central Jersey, and as a result Grasshopper Sparrows are very hard to find outside of a few known breeding locations. New Jersey classifies their breeding population as threatened due to the continued loss of grassland habitat, either to natural succession or new subdivisions.

When I finally left the Grasshopper Sparrow, I figured that nothing else I would see on the walk could beat it, and that turned out to be true. However, it was still a fun walk as I got nice views of some of the bird species that have arrived over the past week. I saw a couple of Bank Swallows, my first of the year, cruising back and forth along the Raritan River. They seemed to be checking out the muddy banks on the opposite side of the river, but I have no idea if they will stick around for the breeding season.

Spring Sparrows on the Move

My local patch has been full of sparrows lately – some moving in and other moving out. Song Sparrows have been the most prominent, as migrating birds inflating the usual crowd. The ones that plan to stick around for the summer are busy setting up territories and singing from the highest perches they can find. The Song Sparrow above was perched on top of a giant brush pile. Song Sparrow was the first sparrow I learned to identify (other than House Sparrows), so I always enjoy hearing them.

In the brush nearby, there were several other sparrows. Some of them were Song Sparrows, but there were also a Chipping Sparrow, a Field Sparrow, and two Savannah Sparrows. One of those Savannah Sparrows had what I think is the brightest yellow supercilium I have ever seen on that species. Chipping Sparrows are now singing all over the park, and there are even some Dark-eyed Juncos left.

Aside from the sparrow show, I saw my first Blue-headed Vireo and Northern Parula of the year yesterday.

Sparrow Migration at Sandy Hook

On Friday, someone reported a Le Conte's Sparrow at Sandy Hook near the marine biology labs. Since this is a species none of us have seen, I went with my mother and sister yesterday to see if it might still be around. Migration was still heavy at Sandy Hook. The field south of Gunnison Road near the labs was loaded with sparrows – at least 9 species by my count. Unfortunately, none of the dozens was a Le Conte's, as far as I could tell. It is difficult to be sure that one was not present since the sparrow action was hot and heavy at times.

Sparrows present along Gunnison Road included Song, Swamp, Lincoln's, Savannah, White-throated, American Tree, and Chipping, along with many Dark-eyed Juncos. Even without the Le Conte's or other Ammodramus types, it was delightful to watch so many sparrows yesterday. Getting the chance to watch Lincoln's and Swamp Sparrows was especially rewarding – the first for its relative rarity and the second since it is one of my favorites. In the same area, there were good numbers of Hermit Thrushes, Eastern Phoebes, both kinglet species, and Brown Creepers. Many of the kinglets seemed to be foraging at or near ground level, often in a grassy lawn. Normally I see kinglets higher in the vegetation structure, so I was surprised to see them acting like juncos.

Raptors included several Red-tailed Hawks, at least two Merlins, and a few Sharp-shinned Hawks. Someone reported a Yellow-breasted Chat at the Gunnison lot a day or two ago, but it was either not present or uncooperative today. However, there was an immature White-crowned Sparrow near Battery Gunnison.

Here are a few photos of the autumn foliage on Sandy Hook:

There were very few butterflies around, but I did see a few Pearl Crescents.

Studying Stress in House Sparrows

Researchers are Radford University are studying the effects of stress on House Sparrows.

As recently as 20 years ago, most research was limited to laboratory rats bred in captivity and monitored through extensive handling by humans.

But wild birds shaped by natural environments and observed remotely by robotic systems may provide a more nuanced picture of biological processes, Davis said.

Once Davis and his students catch some house sparrows, the birds will be transferred to a new aviary at Selu, a research and retreat center owned by Radford University.

There Davis and Selu manager Jeff Armistead have built a state-of-the art research aviary with robotic feeding and monitoring systems. It can house several hundred birds at a time, even separating them into groups so scientists can conduct different studies simultaneously.

Tiny transmitters can be injected into each bird to monitor food intake, hormone levels and other information, which can be shared online with students, faculty and other researchers.

At Selu, Davis' group will observe and analyze hormone and immunity activity in individual birds.

The study of how house sparrows deal with stress hormones may one day lead to better treatments for stress-related illnesses in humans, University of South Florida biologist Lynn "Marty" Martin said.

Martin oversees a large research laboratory devoted to the house sparrow.

Before modern civilization mitigated threats such as starvation, predator attack and exposure to extreme weather, humans evolved in environmental contexts similar to house sparrows.

To survive, humans, like the birds, developed stress response systems that helped them avoid predators (or university professors). But today, those same systems, when triggered by run-ins with a demanding boss or problems at home can, over time, make people sick.

Since House Sparrows are fairly intelligent, the research team has had some difficulty catching them. The birds seem to know to walk under the mist nets rather than fly into them.

Song Sparrows Cooperate to Repel Intruders

Song sparrows listening to the songs of other sparrows can figure out which bird was the intruder in a territorial dispute.

The research has shown that song sparrows can distinguish an aggressor from an "innocent" bird that has had its territory invaded.

Scientists at the University of Washington in Seattle, US, used recorded calls to stage territorial disputes between two birds.

They played the songbird squabble so that neighbouring sparrows were able to hear it and studied the birds' reactions.

After hearing this "dispute", the sparrows reacted aggressively only when they heard the broadcasted calls of the intruding bird. When the victim's song was played the birds did not react.

"This [was] not simply increased aggression to any call they overheard recently in an aggressive situation," explained graduate student Caglar Akcay.

"They seem to be able to infer that the victim is [not at] fault."

The results indicated that, although the birds react defensively to protect their own territories from intruders, they co-operate peacefully with non-aggressive neighbours.

Feverish Song Sparrows

Researchers are studying how western Song Sparrows respond to infections that might cause a fever.

As anyone who has suffered from a cold or flu knows, a high temperature is an unpleasant but important side effect of the body's immune reaction when fighting off pathogens. Laboratory studies, in which the immune responses of animals could be observed in detail, have shown that these responses display significant variations.

Why doesn't every organism defend its body at the maximum possible level of intensity? New immunological theories presume that immune responses are "costly," that is they compete with other energy-consuming processes such as partner selection, territorial behaviour and reproduction. Each individual has limited resources and must, therefore, enter into compromises, so-called trade-offs. This could explain why different species with different living conditions also display variations in their immune responses.

Apparently Song Sparrows do respond with fevers, but only at night, and more vigorously in southern areas. The really cool part of the study is that they found a way to study the birds' responses while the birds were in the wild.

Jim Adelman, a doctoral student at the University of Princeton, and a staff working with Michaela Hau and Martin Wikelski at the Max Planck Institute for Ornithology in Radolfzell have now succeeded in measuring fever and illness-related behavioural changes in various populations of a North American bird species living in the wild, the song sparrow (Melospiza melodia). For the tests, individual sparrows were caught in South California and in the northern state of Washington. To stimulate the immune response in a standardised way, both groups were administered a small dose of bacterial cell walls which causes fever for a limited period of around one day. A control group was left untreated. Following the administration of the injection, a small transmitter weighing approximately 0.5 grams was attached to the birds' backs and transmitted data on both their temperatures and activities over a 20-hour period.

Interestingly enough, the "injected" sparrows showed barely any increase in temperature during the day. However, during the night when, based on their natural biorhythms, birds reduce their metabolism and their temperatures by three to four degrees, clear differences emerged between the two populations: the Californian sparrows recorded a body temperature of over two degrees Celsius higher than the animals in the untreated control group of this population. As opposed to this, the temperatures of the more northern population increased by at most one degree and only during the first half of the night.

The lower fever temperatures of the northern sparrows is explained by their shorter breeding season. Since they need to devote more resources to breeding to cope with a shorter season, they may have less energy left over for producing a fever in response to infection.

Saltmarsh Sparrow: A Most Promiscuous Bird

According to research by Chris Elphick, 95% of female Saltmarsh Sparrows mate with more than one male to produce each clutch of eggs. The average nest had eggs fertilized by 2.5 different fathers. One-third of nests had a different father for every chick. This is a key part of their struggle to produce young that survive and fledge.

The saltmarsh sparrow (Ammodramus caudacutus) is a small, stocky bird that lives along the US Atlantic coast.

Some of their behaviour is unusual for songbirds; males and females do not bond together to form pairs, and the males play no role in caring for chicks.

The sparrows nest amongst the saltmarshes, and are vulnerable to frequent high tides, which can cause a high level of nest loss.

Very high tides occur every four weeks - the same length of time it takes for the sparrow to raise a family.

Professor Elphick suggests that the mating patterns are are a response to this risky environment.

"If they lose their young to flooding, they have to re-nest almost immediately if the new set of young is to survive," he says.

This means that female birds do not have time to look for and invest in the best male partner.

The lack of time increases the likelihood of choosing a poor quality mate. To overcome this, it seems that females mate with several males.

"The females don't want to put all their eggs in one basket so to speak," says Professor Elphick.

The Saltmarsh Sparrow has the highest documented rate of extra-pair mating. However, other birds may have higher rates that simply have not been documented yet. The Greater Vasa Parrot (Coracopsis vasa) and the Superb Fairywren (Malurus cyaneus) have comparable rates.

Song Sparrows Learn by Listening

Song Sparrows (Melospiza melodia) are one of many bird species with complex songs and other vocalizations. Previous research shows that these sparrows learn most of their repertoire. While the ability to sing is innate, the precise songs are not. They learn most of this repertoire during their first year, between the time they leave the nest and the time they migrate. A new study adds some more detail to the picture: young sparrows learn by listening to vocal exchanges among their elders.

For the field study, the researchers radio tagged 11 male sparrows in Seattle's undeveloped Discovery Park. These birds were about two months old and had not yet begun to sing. The park has a year-round resident population of approximately l50 breeding pairs.

To test a young bird's reactions, it was first located by its radio signal and then the speakers were placed about 50 yards from the animal's location. Finally the bird was exposed to five minutes of pre-recorded song, either from pairs of song sparrows, a sparrow and a chickadee (effectively a solo sparrow) or a pair of chickadees (the control condition). All of the sparrow recordings were from birds that were no longer alive, so that the songs the young birds heard were not familiar. Chickadees commonly live in the same habitat as song sparrows, so sparrows are familiar with their songs.

That the juvenile birds approached the simulated interaction of two song sparrows but largely ignored the solo singing of a song sparrow lends support to the social eavesdropping hypothesis proposed by Beecher. This theory says young birds learn to sing by eavesdropping on singing between adult birds, rather than listening to a single bird or directly interacting with an adult.

The abstract for the study is here.

As a side note, American birders will note that the BBC article on this Song Sparrow study contains an egregious taxonomy error.

A Bathing White-throat

Now that April is drawing to a close, we will not have our winter visitors, the White-throated Sparrows, with us for much longer. So to honor their impending departure, here is a series of scenes from a sparrow taking a bath.





All photos taken with the Birdcam. More at Flickr.

House Sparrows Don't Like Thistle

Or so I have heard...

Towhee and Other South Jersey Birds

Yesterday morning we started out at Bivalve. The shell piles smelled even worse than the last time. This time there were many raptors: two Bald Eagles, three Northern Harriers, and a Sharp-shinned Hawk. The latter suddenly popped out of the phragmites; perhaps we disturbed it from a meal. Many Green-winged Teal were visible from the embankment. Other waterfowl included Snow Geese and Black Ducks.

A brief stop at Fortescue yielded more or less the same birds. An eagle was scaring up waterfowl on the marsh, while vultures turned in the distance. No birds were visible on the bay, except for a collection of Herring and Ring-billed Gulls standing on the beach.

Our target stop, however, was the Glades Wildlife Refuge, a preserve owned by the Natural Lands Trust. The entrance is not easy to find, as it is marked only with a generic "coastal heritage site" sign and not the name of the refuge. (This is one element of the Birding Cumberland guide that could use improvement.) The refuge itself is gorgeous. After passing through a woodland dominated by oaks and hollies, a visitor comes out into the middle of a vast salt marsh. A short boardwalk leads to an observation tower. From the tower one can see for miles across spartina and phragmites grasses interrupted only by distant treelines and an occasional house.

From that platform we could see many waterfowl. The birds at close range were mostly Green-winged Teal – about 750 by my count. There were also Black Ducks, Buffleheads, and Northern Pintails. On the horizon we could also see distant skeins of Snow Geese – perhaps a thousand, perhaps more. I doubt that the flocks we saw come anywhere near the total birds in the marsh. As the waterfowl are massing for the journey to their breeding grounds, shorebirds are starting to arrive. A couple hundred Dunlin competed for space on the mudflats with a few dozen yellowlegs. Most of the yellowlegs appeared to be of the Greater variety, but there were a few Lessers in the mix. I enjoyed hearing the yellowleg calls again. As we headed back along the entrance road to the car, we heard a bird calling from near a vernal pool in the woods. The combination of grunts and squeaks sounded characteristic of a Virginia Rail.

On the way back, we stopped at Collingswood to see the Green-tailed Towhee that has been present in a yard there since January 1. It required about a twenty-minute wait before the towhee appeared, but we had plenty of other birds to watch in the meantime. The well-stocked feeders attract many common backyard species, as well as less common ones like Fox Sparrow. Suddenly the towhee emerged near the back fence and started foraged under the bushes. The bird moved plenty of dirt around in that time. Each kick was digging fairly deep into the soil for a bird of that size; it seemed to dig as deep as an inch in a single location before moving on to the next spot. Once we had all had plenty of time to watch, the towhee disappeared, and we departed. I did not take photos, but other birders have. Here is a photo study of the Collingswood Green-tailed Towhee from another New Jersey birder.

Song Sparrows Learning Songs

Most oscine passerines – that is, songbirds other than tyrant flycatchers – have to learn how to communicate with other members of their own species. Call notes, the collection of chips and seets used during flight or foraging, are instinctive. Songs, on the other hand, must be learned. While some of the process is understood, the learning process is still an active area for research.

Tutor choice intrigues Michael Beecher, who leads the research on song sparrows (Melospiza melodia) at the University of Washington. Males grow up to sing between six and 12 distinct songs. Beecher has tested various combinations of young song sparrows and possible mentors....

Young song sparrows move around more than he had expected, Templeton reported at the annual meeting of the Animal Behavior Society, held in August in Snowbird, Utah. Among the 15 young males he could track, each showed up in the territories of at least 20 adult males, making for exposure to some 200 songs.

For the young, eavesdropping is easy, Beecher says. He and his students used stuffed birds of various ages to mimic feathered bystanders hanging around adult male territories. Another grown-up male, albeit stuffed, elicited protests and attacks. But residents tolerated a (stuffed) teenager without a lot of fuss, sometimes flying off to do something more urgent before the researchers had clocked a full observation session.

Young males thus get a chance to watch territorial battles and check out neighborhoods where they could soon compete for their piece of real estate. The youngsters even seem attracted to the noisy conflicts of territorial grown-ups and fly closer as if eager to catch all the details.

Listening and learning songs from a variety of future neighbors could be good preparation for the rough-and-tumble music of the adult world. Seattle’s song sparrows don’t migrate, and males in the sedentary population have plenty of chances to get to know their rivals.

Males face off in territorial disputes by singing to each other, and Beecher has found that repeating a rival’s song back to him counts as a strong move. Learning a variety of the neighborhood songs could mean that a young male has his sassy comeback ready.

There is plenty more in that article, so read the rest.

Sparrow Influx

As I walked into one of the blind sites yesterday morning, I was met by flocks of sparrows. All around me there were dozens of swamp sparrows. They were joined by smaller numbers of savannah sparrows, song sparrows, and even a possible Lincoln's sparrow. Oddly enough, Morning Flight did not pick up a sparrow movement at all, which makes me wonder if these sparrows were new overnight arrivals, or ones that have been hanging around a few days longer. Whenever they arrived, I am glad they are here because I love sparrows, especially swamp sparrows. While cycling towards the site, I thought I heard a kinglet calling from the side of the road, but I passed too quickly for a sure ID.

Unfortunately my Cape May roadkill list has gotten longer in the last few days. Yesterday I added swamp sparrow, and the day before I found a northern parula.

Chippies and Junco

Chipping Sparrows have returned in a big way the past few days. Today there were several in the yard, and many were singing. Dark-eyed Juncos have also been singing and acting very aggressively towards each other.

There are only a few weeks each year when these two species might occupy the same photograph.

At least that is the case in Central Jersey. In the DC area, some Chipping Sparrows will stay all winter.