JULY BCR NEWSLETTER HIGHLIGHTS ENDANGERED SPECIES

The full color, downloadable July newsletter of Bird Conservation Research, Inc. may be accessed at our web site's publications page.  Read about the latest progress on the Forest Bird Survey of Southern New England, and also about Eskimo Curlews and Ivory-billed Woodpeckers.

IVORY-BILLED GHOST BIRDS

I have tucked away in an old file a letter addressed to me from James Tanner.  He was someone who I had known of since my early teens, although when I initially corresponded with him I didn’t let on that I did.  Back in the days before computer generated form letters, he replied to me with a personal and eminently polite note concerning the graduate program at his institution.

At that early point in my scientific career, I was debating in whose footsteps I might wish to follow.  Would it be those of Tanner- the last individual to study the Ivory-billed Woodpecker- a guide across the Styx into the world of ghosts?  Or, alternatively, would it be with someone who could tutor me in the practical and possible?  My decision turned out to be somewhere between those opposing poles- I would follow an individual who had already left this world, John Sage, a founder of the American Ornithologists Union who was ending his career about the time that Tanner was beginning his.   He was also student of Connecticut birds, so continuing on his distributional studies was something that I could actually do. Back in the early 1970s, when it was still possible to sit in a university collection room alone and unsupervised, I would spend my late evenings in front of Sage’s hand-written catalogs and his tray of preserved Passenger Pigeons, contemplating the individual who had collected them.  To this day, I continue largely in Sage’s shadow (see this work here).

But still, thoughts of Ivory-bills never quite faded.  Over the decades intervening between then and now, I have quietly launched solitary albeit unsystematic searches for them.  In all, my searches have been limited in scope, never reaching the magical thousand-hour threshold that seems the minimum for recording low probability events.  But still, I’ve tried and will likely try more.  There are so many thousands of acres of habitat and so few people out really looking that it has seemed just possible that birds might survive somewhere.  The inaccessible and inhospitable nature of the species’ last known refuges- bottomland forests- also appeared to argue that it could be persisting undetected.  Suggestion has also been made- and seems to be backed up by observed patterns of sightings and disappearance- that any remaining birds might be nomadic, so where they are one year is not necessarily where they are the next. Such a possibility would make documenting their occurrence doubly difficult.

Like so many others, when several years ago credible evidence surfaced in Arkansas and Florida (in the latter case, right near where I had been searching myself) that Ivory-bills were still extant, I was exhaltant.  I knew it.  They had to be somewhere.  I watched the videos and listened to the recorded calls posted on the internet.  I found the videos modestly convincing, but the sounds?  Certainly.  In their cadence and phrasing and horn-like quality, it seemed to me that they could be nothing else. I had burned into my head those very sounds from 1930s recordings I had listened to years before.

And then, enter the naysayers.  It is a venerable tradition in academia that critique follows assertion- tiresome and apparently self-serving at times- but most would say essential nonetheless.  In this case several groups took on the evidence presented and negated it point by point.  The images could have been this, the sounds could have been that, statistical inference indicated no no no. 

One suggestion was that the sounds might have been those of blue jays.  I could see why one might think so, but I disagreed.  I’ve just completed, a la John Sage, eight years of surveying Connecticut’s forest birds (see this work here) in which I detected individuals via vocalizations under varying field conditions, topography and distance.  During those years, I counted the better part of two thousand jays and in the process heard what seems likely to be every variation on a jay call theme.  My ears told me that those recordings were not of jays.

And then there was the issue that one of the naysayers had not too many years before edited a volume on Connecticut birds.  In that volume, it stated that it was absolutely, positively and otherwise definitely impossible to survey quantitatively the birds of the entire state.   Well, as it turns out, I just did that, alone and on my own dime, covering over a thousand miles on foot, and not just in summer but in winter as well, and I threw in the whole state of Rhode Island for good measure.  So, assertions to the contrary aside, it was possible.  Dogged determination, persistence and belief go a long way toward making the impossible possible.  I hope traits like these will guide the serious searchers for the Ivory-billed Woodpecker in the years that follow.

It was, thus, with some dismay that I read that one of the key institutions behind re-discovery attempts, the Cornell Lab of Ornithology (Tanner's alma mater, by the way), was discontinuing its intensive field efforts to find birds.  This led me to investigate who was behind the surveys.  From the photos I located, it appeared that the teams consisted principally of young students.  Physical stamina is certainly an advantage in the daunting work required of a survey of this sort.  I discovered my own decreasing stamina limits late last summer when, during field searches for migrant Eskimo Curlews, my legs began giving out after hour upon hour of trudging along Cape Cod dune trails.  However, there is a trade-off between stamina and experience.  Back in Tanner's day, the senior Arthur Allen and Peter Kellogg were out with him during those historic Ivory-bill studies.  I regularly see how my own years of experience give me a substantial advantage over the less practiced in distinguishing subtleties, in understanding how to look and in detecting what others might miss.  I hope this generation of senior Cornell figures has, similarly to their predecessors, made a significant field contribution to the recent efforts.  

Despite professions by some of the scientific elite that the Ivory-bill is either extinct or beyond saving, my feelings remain different.  What I see from published reports is a species that appears to have persisted for a century over significant portions of its former range without any human help.  As our continent's supply of mature bottomland forest continues to grow, we may yet see this bird emerge from its present ghostly status back to that of a resilient and revered member of our wildlife community.

AP ENVIRONMENTAL SCIENCE LAB INTRODUCES FACTORIAL ANALYSIS OF VARIANCE

With the introduction of advanced placement courses into national science curricula,  many students are now exposed to college-level content in the high school setting.  This has permitted inclusion of statistical inference into the classroom- something that has historically been all but absent from high school science.  Especially in a scientific world in which statistical analyses are rapidly expanding in sophistication and complexity, it is essential that prospective scientists be exposed to statistical thought early in their careers.

The factorial analysis of variance falls under the heading of classical frequentist statistics.  It has been  used for many decades in fields like agricultural research to investigate effects of experimental treatments on growth, health and productivity of crops.  Although it offers a reasonably sophisticated approach to examining data, the computations necessary to conduct it are well within the range of most high school students.  Hence, it provides a useful tool for introducing students to statistical concepts.

A lab investigation developed by Bird Conservation Research, Inc. for the AP Environmental Science curriculum, Tomato Growth, combines a traditional agricultural experiment with factorial analysis of variance.  It introduces students to experimental design and statistical concepts like null and alternate hypotheses, probability, controls and interactions.  It demonstrates how statistical tests can be used to verify the existence of trends observed in graphical analysis of data.

Statistical analysis of experimental data has long been a mainstay of agricultural research.

APRIL BIRD CONSERVATION NEWSLETTER NOW AVAILABLE

Welcome to the April, 2013 newsletter of Bird Conservation Research, Inc.  In it, you will find news of our latest progress on analyzing data from the Forest Bird Survey of Southern New England.   You will also find news about our latest products for environmental education.  

Thanks to all of you who have become 2013 BCR members.  Everyone who has done so will be receiving an acknowledgment shortly that can be used for tax purposes. If you haven't yet joined, you may do so simply by clicking on this link.

If you wish to download a PDF version of the newsletter, visit our web site at http://www.birdconservationresearch.org/publications/newsletters.php.

AVIAN HABITAT SURVEY OF SOUTHERN NEW ENGLAND

The Forest Bird Survey of Southern New England, the eight year long project of Bird Conservation Research, Inc. to map density distribution of the region's forest birds, also conducted habitat surveys along its 2220 census points.  The survey examined field conditions in 3417 ha of forest, a sample nearly 100 times that of periodic U.S. Forest Service surveys in Connecticut and Rhode Island.

Like the Forest Service surveys, BCR studies evaluated proportionate cover of major forest types.  In addition, BCR examined forest canopy cover, prevailing tree diameter, understory density, moisture regime, and elevation.  The data are to be used to seek relationships between habitat distributions and distributions of forest bird densities.

Analysis of cover types shows that the forests of Rhode Island (RI in the graph below) are dominated by xeric oak and conifer associations.  Northeast Connecticut (NECT) most resembles Rhode Island in its forest composition; both these regions are extensively underlain by glacial sand and gravel.  The locations most heavily dominated by oak forests are Southeast (SECT) and Southwest (SWCT) Connecticut, where lower elevations and milder climates prevail.  Central Connecticut (CECT) also has a high proportion of oak forests, but has as well extensive cover by more mesic-associated mixed deciduous forests.  Much of the remaining forest in heavily urbanized central Connecticut is indeed in wetter environments.  Northwest Connecticut (NWCT), with the most mountainous terrain in southern New England, has less cover by oaks and more cover by conifer-hardwood forests.  Such forests are generally associated with cooler, northern climates.

FOREST BIRDS OF THE LAST GREEN VALLEY NOW AVAILABLE

Forest Birds of the Last Green Valley, the preliminary report from the eight year long Forest Bird Survey of Southern New England, is now available for free download.  It is may be obtained from Bird Conservation Contributions, the open access scientific journal of Bird Conservation Research, Inc.  Printed copies are also available through the BCR web site.  The report covers the first two years of the survey and provides initial estimates of populations, distributions and habitat use of birds in eastern Connecticut.

Although the report, first published in 2003, was based on limited data and analyses, it provided for the region the first fully quantitative conservation planning resource for birds.  Environmental planners have historically been able to draw upon detailed data on soils, geology and land cover in making conservation decisions, but they have had virtually nothing to use on wildlife.

This first report is to be superseded by Forest Birds of Connecticut and Rhode Island, an atlas of forest bird resources of the region.  The atlas will cover the full eight years of study and, as such, will make use of greatly increased sample sizes.  Duplication of sampling during the study period also will permit assessment of findings in light of temporal variation in bird populations.

FOREST BIRD POPULATION ESTIMATES NEARLY COMPLETE

Final computations of the regional populations of Connecticut and Rhode Island’s forest birds are presently underway.  This is, however, only one aspect of the ongoing analysis of the enormous quantities of data gathered during the Forest Bird Survey of Southern New England.  Upcoming analyses include characterization of the habitats of Rhode Island and western Connecticut as well as analysis of the relationship between habitat and bird populations. When complete, our analyses will result in the publication of Forest Birds of Connecticut and Rhode Island.

Some of the most recently computed population estimates follow:

Black-and-white Warbler:

Northeast CT: 15,671
Southeast CT: 10,983
Central CT: 10,829
Northwest CT: 34,438
Southwest CT: 9,480
RI: 23,332

Blackburnian Warbler: 

Northeast CT: 11,786
Southeast CT: 2,910
Central CT: 1539
Northwest CT: 44,778
Southwest CT: 747
RI: 739

Black-throated Green Warbler:

Northeast CT: 15,373
Southeast CT: 5,392
Central CT: 4,861
Northwest CT: 31,163
Southwest CT: 4,511
RI: 11,365

Yellow-rumped Warbler:

Northeast CT: 1,721
Southeast CT: 0
Central CT: 0
Northwest CT: 6,413
Southwest CT: 0
RI: 2,878

Magnolia Warbler:

Northeast CT: 862
Southeast CT: 425
Central CT: 450
Northwest CT: 6,772
Southwest CT: 0
RI: 0