Up Close and Avian Feeder Videos

Hannah Walker, who works in the Cornell Lab of Ornithology’s multimedia department, recorded these two videos at her backyard feeders.

First up: Chickadees and Titmice

 

You may have seen this second one on the Cornell Lab’s Facebook page.  This is about as close to a Pileated Woodpecker as you can get!

Research News: Can Clark’s Nutcrackers help keep whitebark pine forests alive?

In the coming weeks, students in a Cornell University course studying bird banding and tracking techniques will be contributing a series of blog posts about recent research focused on species that visit feeders in North America. In this first installment in the series, sophomore Kathryn Grabenstein takes a closer look at a study focused on the relationship between Clark’s Nutcrackers and trees in the mountains of the west.

By: Kathryn Grabenstein, Cornell University class of 2014

Recent research demonstrates how Clark’s Nutcrackers help regenerate the forests upon which they rely for their own survival. A member of the Corvidae family, which includes ravens, crows, and jays, Clark’s Nutcrackers occasionally visit bird feeders in the Western half of North America where they can often be seen leaving with a beak full of seed for later consumption. Nutcrackers are scatter hoarders, meaning that they store seeds in many different locations with the intent of returning to eat the seeds at a later date. These seed storage sites are known as ‘caches’—some caches are never retrieved and these seeds may germinate and grow into new plants. In the Western pine forests, nutcrackers play an important role in seed dispersal, caching up to 98,000 seeds per year and spreading them nearly 500 times farther than seed dispersing mammals, such as chipmunks, and nearly 20 times farther than the wind. For one tree species—the whitebark pine—nutcrackers are obligate mutualists, meaning that nutcrackers and the trees depend upon on another. The nutcrackers require the food resource (seeds) provided by the trees, and the trees require the seed dispersal services of the nutcrackers. Whitebark pines, however, are suffering a rapid decline due to invasive insect pests, parasite outbreaks, and fire suppression. A recent study by researchers in Washington State sought to better understand the relationship between nutcrackers and whitebark pine trees.

Clark's Nutcracker on suet feeder by FeederWatcher Kathleen Johnston while visiting La Pine, OR.

Researchers followed 12 birds for four years in the eastern Cascade Mountains using radio telemetry, a technique in which a small radio transmitter is attached to a harness on the back of the birds. Radio waves from the transmitters are picked up by a receiver through an antenna, much like a typical AM/FM radio. Each bird is assigned a separate frequency and researchers can flip back and forth between birds just like flipping through channels on a radio. The radio signals allow researchers to pinpoint the location of the birds and track their movements. All 12 of the birds were followed both on foot and by an airplane as they were caching seeds in an effort to locate their cache sites.

Researchers found that nutcrackers transported seeds as far as 32 kilometers (20 miles) from the harvest location and almost always cached inside their home ranges, even when they harvested the seed from locations beyond the borders of their typical home range. Birds tended to cached more seeds at low elevations than at high elevations. At lower elevations, nutcrackers were more likely to cache below ground, whereas at the higher elevations, 59% of caches were above ground.

This phenomenon of caching most seeds above ground may be found in wetter, colder climates where seeds stored underground may be inaccessible during snowy weather or may deteriorate quickly in wet weather. Whatever the reason, the above ground caching in no way benefits the whitebark pine because it inhibits germination. Although most seeds may be consumed or otherwise prevented from germinating, nutcrackers may be effective seed dispersers simply because of the sheer numbers of seeds that they disperse. Approximately 15% of whitebark pine seed caches were stored in locations that were suitable for germination. Considering that tens of thousands of seeds are stored each autumn, nutcrackers are dispersing thousands of seeds to viable locations, helping to “plant” future generations of the trees. The researchers note that even if only 15% of seeds are cached in habitats where they could germinate and survive, that equates to an impressive minimum of 4,800 seeds dispersed to germination-friendly locations per nutcracker each year.

Kathryn Grabenstein is a sophomore Biology major at Cornell University concentrating in Neurobiology and Behavior. She works at the Lab of Ornithology analyzing paternity in the Red-backed Fairywren, a small insectivorous bird in Northern and Eastern Australia. During winter break 2011-2012, Kathryn had the opportunity to travel Down Under to conduct behavioral observations on this species. She writes that her trip was, “an amazing educational and scientific experience, which included two sightings of Albert’s Lyrebird!”

Source: Lorenz, T.J., Sullivan, K.A., Bakian, A.V., & Aubry, C.A. (2011). Cache-Site Selection in Clark’s Nutcracker (Nucifraga columbiana). The Auk 128:237-247.

Fun Feeder Photo: Wood Ducks!

When Marcia Mason reported Wood Ducks at her feeders in Sechelt, British Columbia, we were a little surprised. So Marcia sent us a photo of her “feeder ducks.”  Enjoy this gem!

Wood Ducks at feeder by Marcia Mason of Sechelt, BC.

Try something different: Spray millet

Millet may not be the first type of seed that comes to mind when thinking of wild bird feeding. A few members of the FeederWatcher’s Forum, however, have had some fun recently by putting out sprigs of millet for their birds. Forum member downeylover writes, “I used twist ties to put out a few sprays of millet as a treat. Its a hit!  The cardinals have been at it non stop but I’ve also seen juncos, chickadees, titmice and house finches enjoying some.”

Cardinals enjoying spray millet by Kim SanFanandre of Long Island, NY

Millet is a small, round seed that is often found in wild bird seed mixes. Some species may toss millet aside while searching for richer foods in the mix such as the black oil sunflower seed. But white millet is readily consumed by some species, particularly birds that feed on the ground. “Spray millet” is millet seed still on the stalk and is usually sold as an enrichment food for captive birds–check your local pet store to see if they carry it. Many native birds will readily consume millet seed including finches, sparrows, towhees, juncos, doves, and cardinals (like the ones seen above).

Note that species such as cowbirds and House Sparrows also love millet, so if you do not want to attract these species, you may want to avoid millet.  Also, try to make sure that you purchase white proso millet, not red millet or golden millet because these other types of millet are not readily eaten by most species.  Spray millet can also be pricey – if you find that spray millet is too expensive, you can also buy bags of white millet seed to spreed on the ground or put in tray feeders.

For more tips on bird feeding, see FeederWatch’s bird feeding page or All About Birds’ feeding page.

Low on birds? Take a look at our live cam!

Many FeederWatchers have been lamenting over low bird counts this winter, but not Tammie Haché – our live FeederWatch Cam host!  If you’re feeling low on birds, why not watch Tammie’s feeder for a while?

Tammie reports: “Things are insanely busy at the web cam!  I’m averaging between 100 and 200 birds at a time in the backyard, mostly Evening Grosbeaks, Pine Grosbeaks and Common Redpolls.  I opened my 5th – 40 lb bag of seed yesterday.  Last winter, I only used 3 bags all season long!”

Take a virtual trip to Manitouwadge, ON and Tammie’s plethora of birds here!

Note to Mac users: make sure you have Flip4Mac installed in order to view the live stream.  You can download it here.

Country birds are bigger than city slickers

Few species do well across a gradient of urbanization from cities to remote farms. Among species that can thrive across these diverse habitats, are there differences between populations found in the city and those in the country? Do urban House Sparrows, for instance, differ from their country cousins?

House Sparrow photo by FeederWatcher Randy Harwood of Rolling Hills Estates, CA.

Recent research along the urbanization gradient in Hungary has shed light on differences between city and country birds. Researchers discovered that House Sparrows in the city were smaller, on average, than individuals of the same species that lived in nearby rural areas. Differences were detected in body mass (weight), the length of the tarsus (a bone in the lower leg), and overall body condition. City-living House Sparrows were consistently smaller and in worse condition than their country cousins. Birds in the most urban settings were 5% lighter, on average, than birds in the most rural areas. These differences remained even after the researchers controlled for the potential effects of year, season, and sex.

One possible explanation for the variation in size is a difference in diet between the city and country sparrows. To control for the influence of diet, the researchers brought adult urban and rural birds into captivity, providing both groups with unlimited amounts of the same food. Despite the identical conditions experienced in captivity, differences in body size and condition remained after several months.

So why are city birds smaller than the birds from rural areas? One possibility is that birds raised in cities do not receive proper nutrition, leading to slower growth rates in the nest and smaller overall body size as adults. Previous research does suggest that nestlings in urban environments tend to be fed lower amounts of food or lower quality foods. Another possibility is that being small in the city helps birds survive. If smaller birds are better suited for the urban environment, we’d expect the size of city sparrows to decline from one generation to the next. Further studies, possibly where birds are raised in captivity under city and country diets, may help determine the importance of diet versus adaptation to the local environment in contributing to the size differences between city and country birds.

Source: Liker, A. et al. 2008. Lean birds in the city: body size and condition of house sparrows along the urbanization gradient. Journal of Animal Ecology 77:789-795.

Bird watching inspiration for 2012

From your friends at the Cornell Lab of Ornithology, here is an inspiring video as we start a new year. Happy 2012.