Journal archives for April 2018

April 08, 2018

Migration

Saturday, April 07, 2018 from 9 am to 11 am

Today was a beautifully sunny day with temperatures in the low 40’s. We decided to head out to Lagoon Road in Hinesburg to look for migrating shorebirds. The habitat there is a prime location for shorebird migrants, as there are open, flooded fields with lots of sedge clumps and some open water areas. On the way home, we stopped at Carse Wetlands, which has multiple different habitat types, from open field, to forest, to open water.

We had quite a successful day. As we arrived at Lagoon Road, we immediately saw two Eastern Meadowlark, which was incredibly exciting, as it was a lifer for several people in our group. After watching them for a while, we got out of the car and walked around, seeing 14 Canada Geese, 4 Mallard, 1 Turkey Vulture, 7 Killdeer, 1 American Crow, 2 Common Raven, 15 European Starling, 6 Song Sparrow, 5 Red-winged Blackbird, and 2 Common Grackle. As we were leaving the area, we were pleased to discover a Red-tailed Hawk and a Northern Harrier, swooping over the field. Then, the highlight of the trip: “SNIPE!!” yelled one of my friends. Sure enough, there were 8 Wilson’s Snipe among the sedge clumps, gazing at us with their beady eyes and disproportionately large bill.

The Killdeer, being a facultative migrant, looked very out-of-place running around in the field covered a few inches of fresh snow from the night before. However, the Killdeer were not fazed, as they begin arriving to their summer breeding range (which spans from New York and Pennsylvania to Nebraska and north through New England, the northern-most mid-western states and across much of Canada) in mid-March, with migration peaks in April. Killdeer are found year-round across much of the United States and Mexico, with some migrating to Central and South America during the winter. Killdeer migration is highly variable, as many birds only move as far south as they need to find food and have access to open water. Killdeer diet consists primarily of invertebrates, like earthworms, grasshoppers, beetles, and aquatic insect larvae, so they do not stay in completely frozen areas where these resources are unavailable. When the snow retreats, Killdeer are able to migrate north and exploit the invertebrates that come to life with the unthawed ground. The plethora of available food sources and breeding space makes migration north for the spring and summer attractive to portions of the population, because an increase in habitat area and available resources leads to a reduction in intraspecific competition.

In contrast to Killdeer, American Crows are residents in Vermont. Although Killdeer are relatively opportunistic feeders, they generally stick to invertebrates, which results in their migration during the winter. American Crows are generalists and completely opportunistic when it comes to feeding, an adaptation that allows them to remain in Vermont during the winter. Additionally, American Crows roost in huge flocks during the fall and winter. There are a number of hypotheses as to why they do this, including information of productive foraging sites (which helps them get through the lean winter months), protection from predators, and protection from the elements. Additionally, American Crows have adapted to roosting in urban areas, again hypothesized to occur for a number of reasons. First of all, American Crows may have figured out that they cannot get shot in urban areas, and may be taking advantage of that. Second of all, urban areas are generally 5 to 10 degrees F warmer than the surrounding countryside, which helps them survive cold winter nights. Finally, roosting in cities provides protection from predators (particularly the Great Horned Owl), both because Great Horned Owls avoid urban areas and the artificial light helps American Crows watch for them.

After we finished birding at Lagoon Rd., we zipped over to Carse natural area. While there, we saw 5 Canada Geese, an American Crow, 2 Black-capped Chickadees, 3 Eastern Bluebirds (first of the year for me!!), 6 Cedar Waxwings, and 2 Song Sparrows. In my excitement about the return of the migrants, I began thinking about the distance these birds traveled. Eastern Meadowlark migration is variable, but those in Vermont will often travel over 621 miles from the southern United States back to Vermont. Canada Geese will migrate as far as 3,000 miles when moving from wintering sites in the southern United States back to the northern regions of their range. Migratory Mallards travel over 700 miles on average when returning to the north after wintering in the southern United States. Killdeer in Vermont must migrate back from Mexico and Central America, with distance averaging at 4,037 miles. Song Sparrows migrate to southern United States and Mexico during the winter, with a return flight averaging at 528 miles. Red-winged Blackbird average migration distance is 53 miles. Northern Harrier migrate depending on food availability, with return flights from southern U.S. and Central America averaging at 2,630 miles. Wilson’s Snipe migration from southern U.S. and Central America back to Vermont averages around 2000 miles. Eastern Bluebird overwinters in southern states, such as Texas, and have a return flight around 1,978 miles. When added together, these migrants traveled over 15,500 miles!

Source Links:
http://www.birds.cornell.edu/crows/crowfaq.htm
https://sora.unm.edu/sites/default/files/journals/jfo/v049n01/p0017-p0034.pdf
http://www.birds.cornell.edu/Page.aspx?pid=1478

Posted on April 08, 2018 18:05 by jpupko jpupko | 20 observations | 1 comment | Leave a comment

April 18, 2018

Field Observation 5: Centennial

5:46 to 7:15 pm on Monday, April 16th, 2018

Today was raining and 40oF. I decided to go on a walk around Centennial, primarily to explore the marshy habitat close to Route 89. The walk started off on a great note, as soon as I got out of the car I was greeted with a beautiful Pileated Woodpecker. I was not able to identify whether the magnificent specimen was a male or female, but he/she skirted around the edge of the parking lot, teasing me by drumming on the opposite side of the tree from where I was standing.

After walking into the woods, I was greeted by 3 Black-capped Chickadees, a group of Song Sparrows, two Blue Jays and two American Crows. The Black-capped Chickadees and Song Sparrows were happily foraging in a brushy, marshy area while the American Crows and Blue Jays were jeering loudly from a distance away. It sounded as if a raptor was present and they were attempting to chase it away.

Then it started pouring. I had meandered to the far side of Centennial so I started back, not expecting to see anyone. However, as I was just about to leave the woods, I heard a small chip. I turned just in time to see a small brown bird fly to a tree near me. After it landed, I was able to identify it as a Brown Creeper!! I was super excited, even though I had seen a group of 4 of them the day before. They are one of my favorite birds – I love their trill-like song and how they pick their way up trees, searching for snacks. It was a wonderful way to end my bird walk.

Posted on April 18, 2018 06:24 by jpupko jpupko | 6 observations | 0 comments | Leave a comment

April 29, 2018

Field Observation 6: Reproductive ecology and Evolution

Friday, April 27, 2018 from 4:3 to 7:15pm

Today was a warm, overcast day with temperatures hovering around 58oF. We went to Redrocks, which has quite the diverse habitat. From Lake Champlain, to the rocky bluffs, to a variety of mature trees including red maple, eastern cottonwood, eastern white pine, white ash, and eastern redcedar, to name a few.

We started off by exploring the vernal pools, looking for herp eggs. As we wandered, we heard a group of Black-capped Chickadees chipping to each other while foraging and an American Crow indignantly squawking, as if threatened. We soon discovered the source of the crow’s distress, a Barred Owl began calling from the eastern white pine stand that the crow had just been sitting in. After listening for a while, I was able to triangulate the location of the Barred Owl and spend some time watching the lovely specimen.

We then headed over to the rocky bluffs, and were met with a symphony of birds, singing out their territory lines and communicating with potential mates. The first bird we observed was a Pine Warbler!! These birds build nests from late March to early June, with females doing most of the nest-building while males sing to mark the territory. Nests are built at the top of large conifer trees. The male we observed was singing in a large eastern white pine, likely guarding his mate as she worked. The habitat that this particular Pine Warbler had found was very prime habitat, as the eastern white pine was very large and appeared to be very healthy. Although the trees were near a few foot trails, the area is relatively undisturbed and surrounded by mature trees. Holding a prime habitat location, such as this one, shows that the male is a very fit individual, as he is able to expend that energy to defend his territory against other males that would be seeking this location. Pine warblers make their nests out of stems, bark, pine needles, spider webs and other materials, which are then lined with feathers. These nests are shaped as deep cups and are located near the end of branches.

As we listened, we heard Tufted Titmice, a Northern Carinal, a Pileated Woodpecker, and two Brown Creepers foraging. All of the birds were just chipping as thy foraged, except for the male Brown Creeper, who was giving his territorial call. Male Brown Creepers generally only call on their breeding groups, but will occasionally sing during migration. Their high, tremulous call is always a treat to hear. The last birds we heard as we stood and listened were a Wood Thrush and a Winter Wren. Male Winter Wrens sing vigorously during the spring breeding season to attract females. Once they have attracted a female, they will flutter around and show her different nests they have built in their territory so she can pick which one she wants to use. They nest in natural cavities that are close to the ground, and tip-up mounds created by fallen trees are very important habitat to them. Within the cavity, a nest is created of grass, moss, and rootlets, which is then lined with animal hair. Male Winter Wrens also sing to defend their territory.

Posted on April 29, 2018 22:07 by jpupko jpupko | 13 observations | 0 comments | Leave a comment

Archives