birds – Page 2 – Biodiversity

Flycatchers Switch to Berrypicking in the Fall

The borders of the Lenfestey Family Courtyard are heavily planted with elderberries and each August and September as they ripen I have great views out my window of the birds that come to feast. There are always the usual bunch, the robins and their young that nested all summer in the Serviceberry, Cardinals of course, and the flocks of Cedar Waxwings that easily navigate the tangle of branches like bands of pirates finding the richest caches of fruit.

But there are Eastern Kingbirds joining the party too. Kingbirds rarely visit the courtyard, preferring the open edges of the trail near the ponds where they gracefully dive and roll, capturing flying insects in their pincer-like beaks. It is strange to see them flapping through the dense foliage of the elderberries, where they tip themselves forward off the branches as they clumsily pluck berries one by one. And while they seem a bit unfamiliar with the technique they do manage to gorge themselves with fruit. Fruit-eating also coincides with a remarkable tolerance in this notoriously aggressive species. Kingbirds will flock together during migration and in their South American wintering grounds.

Scientists have long recognized this feeding switch from insects to fruit in several species of primarily insectivorous birds shortly before and during migration. It was originally thought that the birds switched to fruit as insect populations declined, but this does not seem to be the case. It was also hypothesized that fruit might provide more calories, but nutrition studies showed that while some species did gain weight on fruit others lost weight (Smith et al. 2007). Other research has focused on the advantages of feeding on fruit. Insects require a lot more energy to find and capture and are usually caught on the wing, exposing birds to migrating hawks. Berries offer an easily collected high density food source and the foliage offers cover from hawks and other predators. Studies have also shown that birds do seek out berries that are highest in proteins and lipids (Parrish, 1996).

Just this year scientists have started to look at micronutrients including antioxidants in fruit. Migration is extremely stressful and scientists speculate that ingesting more antioxidants might improve these birds ability to survive during migration and in tropical wintering grounds where birds are packed closer together (McCue et al. 2010).

It has even been suggested by ornithologist Gene Morton (1971) that the white tip on the Eastern Kingbird’s tail might analogous to the bright tail feathers of the waxwings. As they forage tail flicks signal food locations to others in the flock .

Regardless of the physiological reasons migratory birds are switching to fruit, the take-home message is strong. Make sure that migrating birds have access to reliable sources of fruit in the fall. Both Parrish’s and McWilliams’ research suggests that native berries, are superior in nutrition to non-native species. We need to make sure that we preserve native habitats along migratory routes so that birds have reliable high quality food during stop-overs.

Parrish (1996) also argues for us to become better land stewards of our own yards. “Conserving native habitat in a backyard is simple and inexpensive,” he said. “Many songbirds will even use small, yard-sized patches of these natural landscapes during migration, providing people with exciting opportunities for bird observation–and providing the birds with the critical fuel for a long journey south.”

References

McCue, M. D., O. Sivan, S.R. McWilliams, and B. Pinshow (2010) Tracking the oxidative kinetics of carbohydrates, amino acids, and fatty acids in the house sparrow using exhaled 13CO2. Journal of Experimental Biology, in press.

Parrish, Jeffrey D. (1997) Patterns of Frugivory and Energetic Condition in Nearctic Landbirds during Autumn Migration. The Condor Vol. 99, No. 3 (Aug., 1997), pp. 681-697

Morton, Eugene S. (1971) Food in migration habits of the Eastern Kingbird in Panama. The Auk: 88: 925-926.

Smith, Susan B., Kathleen H. Mcpherson, Jeffrey M. Backer, Barbara J. Pierce, David W. Podlesak, and Scott R. Mcwilliams (2007) Fruit Quality and Consumption by Songbirds During Autumn Migration . The Wilson Journal of Ornithology 119(3):419–428

Turner, Scott (1996) Study shows songbirds switch from bugs to berries to fuel fall migration. Brown University news Bureau. http://www.brown.edu/Administration/News_Bureau/1996-97/96-019.html

Point au Sable Bird Survey: October 1, 2010 by Erin Gnass

In a short amount of time, undergraduate student, Aaron Groves, and I were able to trek over to Point au Sable and perform just one point count along the shoreline before the downpour of rain began! Upon arriving at the Point, we noticed that the landscape had changed drastically since we had last been there a few months ago. The shoreline was completely covered in the invasive Phragmites australis, making it nearly impossible to view the bay of Green Bay. Regardless, many of the small passerines did not seem to mind this invasive. We found numerous Black-capped Chickadees, Song Sparrows, and one Myrtle (Yellow-rumped) Warbler foraging within the Phragmites and using it for cover. We also observed the following species: Great Egret, Great Blue Heron, Mallard Duck, Canada Geese, Ring-billed Gull, Red-winged Blackbird, Common Grackle, Ovenbird, Downy Woodpecker, Gray Catbird, White-breasted Nuthatch, American Crow, Blue Jay, and American Robin. Upon hearing the chatter of the Belted Kingfisher and the ever-present European Starling, the rain slowly started to pour, at which point Aaron and I left for the day. We observed a total of 19 species.

Brown, Kewaunee, Shawano, and Oconto Bird Surveys: May 26 to June 24, 2010 by Erin Gnass

As I mentioned in one recent blog posting entitled “May 26, 2010 by Erin Gnass,” I performed bird surveys for the greater part of the month of June for my thesis project—the index of ecological condition model, as applied to northern hardwood forests of Wisconsin. In order to most appropriately create this model, I surveyed additional hardwood forested sites considered to be of poorer forest condition so as to sample across a wide range of environmental condition. This enables the model to be more accurate and effective at calculating forest condition. Therefore, I went in search of hardwood forest sites on both public and private lands near and within heavily managed, fragmented, and human-disturbed or developed areas. Within Brown, Kewaunee, Shawano, and Oconto counties here in east-central Wisconsin, I found 27 sites that I surveyed, with the much-appreciated assistance of Joan Berkopec (the same wonderful volunteer who helped with the Wild Rivers Legacy Forest surveys and the Nicolet National Forest Bird Survey that I described in the two previous posts).

From May 26 until June 24, I observed 49 total species at these 27 additional sites, including the following species of interest:

Seven warblers: Chestnut-sided, Common Yellowthroat, Mourning, Northern Waterthrush, Ovenbird (in moderate numbers), Pine, and Yellow Warblers

Seven woodpeckers: Downy, Hairy, Northern Flicker, Pileated, Red-bellied, Red-headed, and Yellow-bellied Sapsucker Woodpeckers

Four flycatchers: Eastern Phoebe, Eastern Wood-Pewee (in moderate numbers), Great Crested (in moderate numbers), and Least Flycatchers

Three thrushes: American Robin (in moderate numbers), Veery, and Wood Thurshes

And one vireo: Red-eyed Vireos (in large numbers)

Please feel free to look at the photographs that I took shown below:

WI DNR sugar maple forest plot in Shawano County

While scouting out potential survey sites in Brown County, I heard then observed this spectacular Mourning Warbler pictured here

Red-headed Woodpecker that I found at the Brown County Pet Exercise Park, which is full of sugar maple hardwoods

One of the two Red-headed Woodpeckers at their nesting cavity site

Thank you to professional photojournalist, Scott Giese, my boyfriend, for taking these additional photographs of me while I completed a bird survey in Brown County:

Me, Erin Gnass, obtaining a GPS coordinate at a bird survey site in Brown County

Recording data for a bird survey in Brown County

Me, Erin Gnass, trying to obtain a visual observation of a bird during a bird survey in Brown County

June 11-13, 2010: Nicolet National Forest Bird Survey by Erin Gnass

Every year since 1987, a large group of ornithologists have performed breeding bird surveys within the Nicolet National Forest (NNF; see the Nicolet National Forest Bird Survey: (http://www.uwgb.edu/birds/nnf/) in northeastern Wisconsin, now contributing to well over 40,000 records of birds consisting of over 200 total bird species. Whether you are an ornithologist by profession, a volunteer, a student, a back-yard birder, the state’s best expert, or a complete novice who has never seen a Canada Goose in your life, absolutely anyone can come and assist in the survey! Luckily, I was able to be one of the group leaders and engage myself in the survey for the very first time. Having heard about how much fun and exciting it is to participate in such a wonderful annual event, I was not disappointed in the slightest!

On the first day of the survey, I led a small team birders consisting of a young couple and another woman to pine and hardwood forests and a few beautiful bogs. Although the sites were not as biodiversity rich as other sites within the Nicolet National Forest, we were able to observe many interesting but “usual suspect” birds, such as the Ovenbird, Red-eyed Vireo, Chipping Sparrow, Eastern Wood-Pewee, Rose-breasted Grosbeak, American Robin, Brown Creeper, Blue Jay, Black-capped Chickadee, Black-throated Green Warbler, Alder Flycatcher, Yellow-bellied Sapsucker, and many others. After this first morning of surveys, a large group of us, including (some of my favorite ecologist/biologist friends) UWGB undergraduate student, Aaron Groves, former UWGB Environmental Science & Policy graduate student, Kathryn Corio, Ron Eichhorn (who helped the Nature Conservancy and me with the WRLF project), and a few others went out to a bog near the NNF to look for interesting plants and birds. A few of us chased down a Palm Warbler while others observed uncommon plant species. Please see the photographs that I took down at the bottom of this posting. Thank you to all of the botanists in this group who showed me these beautiful plants.

On the second day, graduate student, Nick Walton, joined our group and helped to lead the surveys. Near the end of one of the last surveys of the day, we heard a nearby soft chickadee-call where we discovered two Boreal Chickadees—the highlight of my entire summer. Not only did these individuals continue singing throughout the remainder survey, they flew low in the trees only ten meters away from us for quite a few minutes. Not many people have the opportunity to view this species in particular because they are considered an uncommon, northern U.S./Canada dwelling species. Thus, when we shared the news with other birders upon returning to the field houses, everyone expressed their surprise and excitement to us. What a thrilling day it was.

I look forward to next summer’s bird surveys at the Nicolet National Forest.

My photographs:

Me, Erin Gnass, leading one of a few surveys in a Nicolet National Forest bog

One of a few beautiful bogs that we surveyed.

After the first day of surveys, a small group and I went in search of plants and birds around the bog pictured here.

UWGB undergraduate, Aaron Groves, at the bog bird watching.

Ron Eichhorn and Aaron Groves trying to identify a plant.

UWGB undergraduate, Aaron Groves, and his mother, former UWGB Environmental Science & Policy graduate student, Kathryn Corio

Undergraduate student, Aaron Groves, and I found a previously made teepee-like structure on a hill leading down to the bog.

May 30 to June 5, 2010: Wild Rivers Legacy Forest by Erin Gnass

One of the many exciting bird research projects that I helped to investigate this summer was with the Nature Conservancy (TNC) in the Wild Rivers Legacy Forest (WRLF) north of Armstrong Creek in northern Wisconsin. With a field crew of eight people, many of us living in one field house, we not only gathered very useful bird survey data for TNC and my graduate thesis project, but we were also fortunate enough to listen to and observe many unique and beautiful bird species. Every afternoon or evening, we met as a group to decide how to break apart all of the required bird survey sites within the forest. Some of us went out in pairs while others surveyed independently to perform as many bird point counts as possible between the half hour prior to dawn until 9:30 AM (the short window of time that breeding birds are allowed to be surveyed). Depending on the terrain, distance between points (via car or on foot), and weather, many pairs or individuals performed as few as 5-6 surveys to as many as 12 in a morning! Therefore, we finished all 200 bird survey sites in the WRLF and the 23 additional sites of poor ecological forest condition in one week’s time!

For some of the bird sighting highlights of this week during the first week of June, we viewed 73 total species within the WRLF including:

16 warblers: American Redstart, Black-and-white, Blackburnian (in large numbers), Black-throated Blue, Black-throated Green (in large numbers), Canada, Common Yellowthroat, Chestnut-sided, Magnolia, Mourning (in large numbers), Myrtle (the official name of the eastern population of the Yellow-rumped Warbler), Nashville, Northern Parula, Northern Waterthrush, Ovenbird (in large numbers), and Tennessee Warblers

Six flycatchers: Eastern Kingbird, Eastern Phoebe, Eastern Wood-Pewee (in large numbers), Great Crested, Least (in large numbers), and Yellow-bellied Flycatchers

Six woodpeckers: in comparison to last year’s data, we observed many more woodpecker individuals: Downy, Hairy, Northern Flicker, Pileated, Red-bellied, and Yellow-bellied Sapsucker (in large numbers) Woodpeckers

Five thrushes: American Robin (in large numbers), Hermit Thrush (in large numbers), Swainson’s, Veery, and Wood Thrushes

Four birds of prey: Broad-winged Hawk, American Kestrel, Barred Owl, and Red-shouldered Hawk

Two vireos: Red-eyed (in large numbers) and Blue-headed Vireos

And several other birds of interest included: Black-billed Cuckoo, Black-capped Chickadee (in large numbers), Blue Jay (in large numbers), Brown Creeper, Common Raven, Chimney Swift, Evening Grosbeak, Indigo Bunting, Purple Finch, Rose-breasted Grosbeak (in large numbers), Red-breasted Nuthatch, Scarlet Tanager (in large numbers), White-breasted Nuthatch, White-throated Sparrow (in large numbers), Winter Wren, and Yellow-billed Cuckoo.

In comparison to the 200 sites of the WRLF, we only observed 47 total species within the sites of poor ecological forest condition, including many of those observed within the WRLF. In these additional sites, however, we also observed the Eastern Bluebird, Eastern Meadowlark, Golden-winged Warbler, Ring-necked Pheasant, and Yellow-throated Vireo, which were not observed during point counts in the WRLF.

For fun in the afternoons, we would gather for lunch at a nearby lake, such as Savage Lake, and enjoy the Black Terns, Sandhill Cranes, and Common Loons, which foraged within a few hundred meters of us. Other days we searched for different bird species (e.g. Bobolink) and other walks of life, such as dozens of dragonfly species, as expertly identified by Ron and Joan. We ran into several deer and quite a few black bears, including one close call during a survey that I was conducting by myself. Around minute three of one ten-minute bird point count survey that I was doing, a large black bear peered through thick brush about 25 meters away from me. After shooing it away from me, it still remained close, only about 200 meters away. Upon completing the bird survey and heading back to my car, it stood on its back legs and kept a close watch over me! Thankfully, it continued to forage and stay clear of me.

In one short week’s time, our dedicated and tireless field crew performed many surveys, which provided this study with incredibly useful data that will contribute towards a vastly important conservation project for the future. Luckily, I had some of the most fun that I have ever had working on a bird field crew and am grateful to be a part of this project. Thank you to all of those expert birders on this crew who helped me to become a better birder!

Please take a look at some of the photographs that I took during this week.

John Wagner and Joan Berkopec with the field crew dog, Pogo

Sandhill Crane foraging along the muddy edge of a lake

Forest road leading to a few of the last bird surveys that I performed just north of Goodman, WI

American Bittern

Keen-eyed botanist Gary Fewless spotted this American Bittern (Botaurus lentiginosus) in the Cofrin Arboretum. American Bitterns used to be fairly common in the large marshes on the west side of the Bay of Green Bay, nesting in cattails and in sedge meadows in Atkinson, Sensiba, and Peters marsh. In recent years, as Phragmites australis has invaded and replaced cattails in much of the marshes in northeast Wisconsin, we have seen a decline in the numbers of nesting pairs of American Bitterns.

The loss of large wetland areas to development and degradation by invasive plants like Phragmites and pollutants has taken a toll on bittern populations in the United States. Overall American Bitterns are half as common as they were 40 years ago.

This individual is the first to be sighted on the UWGB campus and is probably a young bird that is looking for suitable habitat as it prepares to migrate. According to Richter Museum Curator Tom Erdman, these individuals often return to a location they sampled the previous fall. So perhaps this one might return to nest in the spring.

Nature Conservancy Bird Survey: May 26, 2010 by Erin Gnass

Because I have been in the process of preparing for my graduate thesis field work this summer, I have not had a chance to perform any additional bird surveys at Point au Sable. I will be heading to the northern hardwood forests of Wisconsin on Saturday to assist in performing over two-hundred bird surveys with the Nature Conservancy (TNC) for my thesis research. For my thesis project, I am developing a probability-based ecological indicator model for over 65,000 acres of forested land that is managed by TNC, the state of Wisconsin, and timber investment management organizations in the Wild Rivers Legacy Forest (WRLF). Based on an environmental gradient (ranging from degraded to pristine forest conditions), this ecological indicator will utilize the presence and absence of assemblages of bird species to indicate the ecological condition and conservation health of the forested lands of the WRLF. This indication of ecological condition will provide timber managers within the WRLF assistance in monitoring and managing these forests in a sustainable manner for both humans and wildlife.

In preparation for the model, TNC surveyed sites in the northern hardwoods of Wisconsin for forest bird species in the summer of 2009. This summer, I will be fortunate enough to join the team of ornithologists and survey the same sites as well as others, starting this Sunday. Additionally, in order to survey sites across the entire environmental gradient, my graduate advisor, Dr. Bob Howe, and I are surveying additional areas of varying forest condition including fragmented, isolated, and/or human-used areas in the Brown County area in order to most appropriately create this ecological indicator model. Therefore, we started these additional surveys yesterday morning in areas including and surrounding Brown County. All of this data will then ultimately contribute towards the conservation, protection, and sustainable use of northern Wisconsin hardwood forests.

Yesterday, we went to the managed forests of the Reforestation Camp in Suamico, Wisconsin and found 31 total bird species, including many species of particular interest: Mourning Warbler, Northern Waterthrush, Pileated Woodpecker, Scarlet Tanager, Veery, and Yellow-bellied Sapsucker. We also found American Crow, American Goldfinch, American Robin, Black-capped Chickadee, Blue-gray Gnatcatcher, Brown-headed Cowbird, Blue Jay, Canada Goose, Common Yellowthroat Warbler, Downy Woodpecker, Eastern Wood-Pewee, Great Crested Flycatcher, Gray Catbird, Hairy Woodpecker, House Wren, Indigo Bunting, Mourning Dove, Northern Cardinal, Ovenbird, Red-bellied Woodpecker, Red-eyed Vireo, Red-winged Blackbird, Sandhill Crane, White-breasted Nuthatch, and Wild Turkey.

Although I will be in northern Wisconsin for the next few weeks, I will provide a few reports about my thesis work and the annual Nicolet National Forest Bird Survey (June 11-13) when I return to Green Bay. Then, once I am back from field work, I will survey Point au Sable again and provide weekly updates. So please stay tuned!

Point au Sable Bird Survey: May 17, 2010 by Erin Gnass

With bright sunshine, nearly 60 degrees in temperature, and northerly winds over the weekend, we found many new species and the most total species observed for the season in one morning-a total of 59 species! We observed approximately a dozen Common Goldeneyes performing mating rituals off shore near a few American White Pelicans. A dozen Double-crested Cormorants, Canada Geese, Mallard Ducks, and screeching Caspian Terns passed along shore and overhead through the morning. Spotted Sandpipers and Sandhill Cranes also continue to use the Point. Despite many of the interesting species we observed today, we found a few broken American Robin egg shells, which we have found a few times around the Point. Sadly, the eggs might have blown out of different pair’s nests during some intense wind or rain storms that we have had this April and May.

Of the newest arrivals were Red-eyed Vireos, Yellow-throated Vireos, Least Flycatchers, and Yellow-bellied Flycatchers! While I stumbled upon a Northern Waterthrush out in the open, Aaron spotted our season’s first Black-billed Cuckoo high in an aspen tree, laying fairly still along a branch. We later found it lower in a shrub, perhaps resting after arriving to the Point overnight. And one short of our record of total warbler species observed in one day for the season, we observed 13 total warbler species this morning, including Northern Waterthrush, Tennessee, Golden-winged, Magnolia, American Redstart, Palm, Blackburnian, Yellow, Yellow-rumped, Common Yellowthroat, Black-and-white, Ovenbird, and Nashville Warblers. We continue to observe Warbling Vireos, Rose-breasted Grosbeaks, Swamp Sparrows, Blue-gray Gnatcatchers, House Wrens, Bald Eagles, Baltimore Orioles, Song Sparrows, and many more interesting and magnificent species of birds.

Observers: Erin Gnass and Aaron Groves (Thank you very much, Aaron, for accompanying and helping me this spring season and best of luck with your Cofrin student research summer field work!)

Point au Sable Bird Survey: May 14, 2010 by Erin Gnass

Although the morning started out a little chilly at the Point, it didn’t take very long for the air to warm and the birds to start singing and being active. Shortly after arriving and completing our first bird survey, a season’s first, beautiful white Great Egret flew over the Bay and landed within twenty five meters of us! It quickly began to forage along shore looking for fish and then flew further down the shoreline, at which point I was able to photograph this elegant bird. Additionally, we found ten species of warbler, including our season’s first Chestnut-sided and large numbers of Common Yellowthroat, Yellow, Yellow-rumped, and Palm. In fewer numbers but just as wonderful, we found Cape May, Blackpoll, Black-throated Green, Black-and-white, and Ovenbird warblers.

Throughout the entire Point, we found many regular, abundant species including House Wrens, Blue-gray Gnatcatchers, Chimney Swifts, and Gray Catbirds. Although less abundant, we also observed a few rather conspicuous Rose-breasted Grosbeaks, Warbling Vireos, and Swamp Sparrows. Around the same area that we were walking two days earlier, we observed and heard a melodious Wood Thrush near the center of the Point within dense vegetation. We also observed large numbers of Tree, Barn, and Northern Rough-winged Swallows foraging for flying insects off shore and near the center of the Point. All together, we recorded 40 species.

Observers: Erin Gnass, Aaron Groves, and Ashley Fehrenbach

Photographs by me:

Great Egret, foraging shortly upon arrival to the Point

Point au Sable Bird Survey: May 12, 2010 by Erin Gnass

Despite how cold it was upon arriving at the Point, we found the forest and shoreline to be quite active with many new and exciting season’s first migrant bird species! We were incredibly fortunate to stumble upon some very interesting species: Spotted Sandpiper (three different individuals around the Point), Blackpoll Warbler, American Redstart, Swainson’s Thrush, Wood Thrush, Chimney Swift, Cliff Swallow, and White-crowned Sparrow! Although much lower in numbers, Yellow-rumped and Palm Warblers continue to forage and use the Point as they pass through the Green Bay-area and head north for the breeding season. House Wrens, Warbling Vireos, Blue-gray Gnatcatchers, Common Yellowthroats, Yellow Warblers, and Tree Swallows, however, were still quite abundant and observed at several different locations around the Point.

Observers: Erin Gnass, Kari Hagenow, and Aaron Groves

Note: Nick Walton will no longer be assisting with the Point au Sable surveys for the season because he has headed north for his summer field work searching for and monitoring the nests of the Great Lakes endemic, Kirtland’s Warbler! He will return later in the summer and fall to continue surveying the birds at the Point.

Some photographs, taken by me: