Winter Finch Forecast

Purple Finch / USFWS Photo

Even though the season just turned to autumn, Ron Pittaway has issued his annual forecast for the migration of winter finches and associated birds in eastern Canada and the northeastern United States. This is a useful service for birders since many finch species do not follow the same migration pattern each year. Instead they move in response to the availability of seed crops, which vary from year to year. If the seed crop in the boreal forest is really good, finches stay in the boreal forest. If the crop is sparse, they move to a location with a better crop, which could take them south, west, or east. Heavy southward movement of one or more finch species is known as an "irruption."

This year the seed crops are good, so mass southward migration is unlikely. These species seem the most likely to wander south:

PURPLE FINCH: Purple Finches will be uncommon in Ontario, but probably in higher numbers in Atlantic Canada, New York and New England where cone crops are excellent. A few may frequent feeders in southern Ontario. The Purple Finch has declined significantly in recent decades. Some suggest it declined due to competition with the House Finch. However, the drop in numbers began before House Finches were common in eastern North America and also occurred where House Finches were absent. A better explanation for the decrease is the absence of large spruce budworm outbreaks that probably sustained higher Purple Finch populations in the past....

PINE SISKIN: The nomadic siskin is a spruce seed specialist. There are currently large numbers of siskins in Yukon including a high proportion of hatch year birds. They will move because the spruce crop is average in Yukon and Alaska this year, possibly coming to the East. Siskins are expected to be widespread across Ontario this winter. Good numbers are likely to be drawn to the excellent spruce and hemlock crops in Atlantic Canada, New York and New England....

RED-BREASTED NUTHATCH: This nuthatch is a conifer seed specialist when it winters in the north and its movements are triggered by the same crops as some of the boreal finches. There has been very little southward movement indicating that this nuthatch will winter in areas with heavy cone crops such as the boreal forest, Quebec, Atlantic Canada, New York and New England States.

Read the full report for information on the other species. To read more about which birds are classed as winter finches and their habits, see this essay by Ron Pittaway (pdf).

Loose Feathers #309

Chaffinch / Photo credit: Michael Apel

Bird and birding news

• Recent research has identified the Italian Sparrow (Passer italiae) as a distinct species. The Italian Sparrow is an unusual example of a species that evolved out of hybridization between two other species, in this case, House Sparrow (Passer domesticus) and Spanish Sparrow (Passer hispaniolensis).
• A study of captive Humboldt Penguins at the Brookfield Zoo suggest that penguins have a well-developed sense of smell that allows them to identify relatives and reduce inbreeding.
• A disease called trichomonosis is spreading from Britain's finches to mainland Europe. The disease mainly affects Greenfinches and Chaffinches.
• The owners and operators of the Cosco Busan oil tanker have agreed to pay $44.4-million to settle civil suits arising from the 2007 oil spill in San Francisco Bay, which killed thousands of birds and coated beaches and wildlife habitat with oil. 
• Satellite transmitters may have harmed some Red Kites, either by chafing and causing lesions or by hampering their breeding.
• San Francisco is implementing a bird-safe building code.
• NPR celebrates Bar-tailed Godwits for their toughness.
• The Sonoran Desert Bald Eagle population was removed from the Endangered Species List.
• Most primtive birds of the Cretaceous were probably killed by the same meteor that killed the dinosaurs.
• The size of a songbird's brain affects how many songs it can learn.

Nature blogging

• Net Results: Geolocators on catbirds
• Biodiversity Heritage Library: Book of the Week: Birds and Their Nests
• Beetles in the Bush: Not all Florida tiger beetles are rare 
• Myrmecos: The Current State of Ant Genomics
• mocosoco Birds: Hudsonian Godwit, Stilt Sandpiper, Bridgewater Shorebird Recap, 9-22-2011
• Earbirding: The Next Junco
• March of the Fossil Penguins: Baby Penguins in the Fossil Record
• Wanstead Birder: Semipalmated Sandpiper, Drift Reservoir
• Bird Light Wind: Gull Fate
• ABA Blog: BOU splits with AOU relevance
• Bug Eric: Spider Sunday: Pirate Spiders
• AnimalWise: They’ll Take Two in the Bush – Crows and Ravens Show Patience

Environment and biodiversity

• Tree rings reveal that bristlecone pines have grown more in the past half-century than at any other time in the past 3,700 years. Warmer temperatures are likely to be the cause of the change.
• Scientists have discovered a new disease carried by the same ticks that carry Lyme disease.
• Camera traps have turned up more Sierra Nevada red foxes than expected.
• Mapping indicates that Yasuni National Park in eastern Ecuador is the most biodiverse spot in the Western Hemisphere, and possibly the world, but it is threatened by oil exploration.
• Bowhead whales are using the newly melted Northwest Passage to move across the northern tier of Canada.
• The US Postal Service has issued a new stamp to fund conservation.
• The cost of removing four dams along the Klamath River is likely to be a third less than projected. Meanwhile, two dams are slated to be removed along the Elwha River to allow salmon to spawn upstream again.
• Twelve new species of frogs have been found in India, along with three extinct ones. One of the newly-discovered frogs makes cat-like sounds.

S is for Snakeroot

One of the plants blooming profusely at the moment is White Snakeroot (Ageratina altissima). Snakeroot is comfortable in a variety of habitats, from thick shade to partial sun. It is especially at home in open woods and thickets, but I have also seen it growing in more open areas. Snakeroot produces clusters of small white flowers on long stems. Its leaves are vaguely heart-shaped and roughly toothed. Snakeroot is one of many species that were formerly grouped in genus Eupatorium, so you may occasionally see its scientific name given as Eupatorium rugosum in older publications.

Snakeroot seems to be much unloved. Part of the reason is its weediness; it often grows in dense patches, spreads rapidly, and can take over an area if left unchecked. While I appreciate the beauty of its white flowers, the large, rough leaves might not be aesthetically appealing to everyone. Another reason for its poor reputation may be its toxicity. White Snakeroot produces tremetol, a toxin that produces severe intestinal distress if it is ingested. In the 19th century, tremetol often poisoned humans who had consumed milk from cows that had eaten snakeroot, a disease known as milk sickness.

Despite its bad reputation, not every animal is harmed by the plant's toxins. Many insects find snakeroot useful for food. According to the HOSTS database, five species of moths have been recorded using White Snakeroot as a larval hostplant. They are Clymene Moth (Haploa clymene), a leaf blotch miner moth (Leucospilapteryx venustella), Hitched Arches (Melanchra adjuncta), Ailanthus Silkmoth (Samia cynthia), and another silkworm moth (Samia walkeri).

Besides that, many insects use snakeroot for nectar, like this Asian Tiger Mosquito (Aedes albopictus). I have also seen various bees and hoverflies nectaring at snakeroot, but I cannot find an image from my files.

Others just rest on its leaves, like this picture-winged fly (Delphinia picta).

Yesterday I found something I had not noticed before in the snakeroot patches in the backyard. Many snakeroot plants had long lines of tiny aphids up and down the stems. Of course, where there are aphids, there are likely to be ants, so there were also many ants walking up and down the stems to tend to the aphids. Thanks to Alex Wild for identifying these as winter ants (Prenolepis imparis). Click through the photo above to see more of the ants.

There was a particularly dense cluster of aphids near the top of the plant, and there were ants along with them. This cluster was harder to photograph because the flower head was in the way. While snakeroot may be nutritious to some insects, I still would not suggest eating it yourself. However, unless there is a risk of accidental ingestion (by a pet or small child, for example), it may be worth leaving some snakeroot in place for insects to use.

Least Skipper

I found this Least Skipper on my local patch yesterday afternoon. I accidentally flushed it off of some asters, but it landed nearby. It then sat very still while I took a series of photos of it. I almost turned my ankle while I was getting into position to photograph it because a deep rut hidden in the long grass. As you can guess from the name, Least Skipper is a tiny butterfly. It prefers wet meadows, marshes, and streams.

Another Example of Crow Intelligence

As if we needed further evidence for the intelligence of corvids, researchers studying New Caledonian Crows have found them using mirrors to solve problems.

Scientists captured 10 wild birds and placed them in large cages in order to record their behaviour in response to mirrors.

All the crows reacted to seeing their reflections as if they were encountering another crow; the birds made rapid head movements, raised their tails and even attacked the reflection.

Lead researcher Felipe S Medina Rodriguez said the crows' antagonistic reaction to their mirror image "was not surprising". He explained that an animal usually had extensive exposure to mirrors before it began to display an understanding that the image it was seeing was itself....

The second part of the experiment, though, revealed some surprising findings.

The scientists devised a task to test whether the crows could use mirrors to locate cubes of meat that were hidden from direct view.

All of the crows tested appeaed to understand how the meat's reflection correlated to its location.

"We were surprised by how quickly the crows learnt to use a mirror reflection to locate hidden food," said Mr Medina.

"Usually, it takes longer for an animal to start using the properties of mirrors to have access to otherwise non-visible objects."

Further tests ruled out the possibility that crows were using a sense of smell to find the food. Other animals that can interpret images in mirrors include African grey parrots, great apes, dolphins, monkeys and Asian elephants, but apparently these New Caledonian Crows were the first to do so without extensive prior contact with humans.

The linked article also contains a summary of a study on the problem-solving skills of Great Tits and Blue Tits.

Backyard Insects on Goldenrod and Sedum

With the approach of autumn, a lot of summer flowers are starting to die back and be replaced with seed heads or berries. The insects that made such intensive use of them are also fewer in number. A few types of flowers still are blooming, though, and if you look closely you can still see insects using them.

Goldenrod (Solidago sp.) is one of the most prominent plants of autumn meadows and wildflower gardens. Insects notice and take advantage of their rich yellow flower bracts. One of the insects making use of the goldenrod in my backyard was this fly. It appears to be Trichopoda pennipes, a new species for me. It is in a group known as "feather-legged flies," in reference to the hairy tufts on their hind legs.

Also nectaring at goldenrod were several mosquitos, including this one.

Finally, this wasp, which appears to be Eumenes fraternus, was sitting on top of one of the Sedum plants. It barely moved at all while I ran off a series of photos, which made me wonder if it was really sipping nectar or doing something else.

Migration at Scherman-Hoffman Sanctuary

Yesterday I went to Scherman-Hoffman Wildlife Sanctuary in search of migrating songbirds. The weather conditions favored inland hotspots, so I expected some diversity. As it turned out, warblers were rather sparse, so that I only recorded four species (Common Yellowthroat, Bay-breasted, Palm, and Magnolia Warblers). Blue Jays, American Robins, and Northern Flickers were all present in numbers above what I would normally expect. The most noticeable migrants, though, were Broad-winged Hawks. I saw two kettles, one with about 40 individuals and another with about 20 individuals. Another group apparently saw 100 hawks in a single kettle. Aside from those, I noted one migrating Osprey.

Fall wildflowers are blooming in the sanctuary's meadows, including many types of asters. There were, of course, a lot of New England Asters (Symphyotrichum novae-angliae). I have identified these three additional species as best as I can. The one above appears to be a Smooth Aster (Symphyotrichum laeve). The one below seems to be Purplestem Aster (Symphyotrichum puniceum). The one at the bottom looks like a Calico Aster (Symphyotrichum lateriflorum). If you see a better identification for any of them, please leave a comment.