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Ohio Winter Bird
Atlas
FAQ's
Are
there any other winter Atlases for comparison?
There is a Winter Atlas currently under way for San
Diego County California. Done on an entirely different
scale, this census also holds to a meteorological winter
recording period (1 Dec. through 28 Feb.). In Ohio, such
a time period would corrupt the purpose of identifying
the over wintering species. As part of the Mississippi
GAP analysis program, that state's vertebrate atlas
includes gathering data on birds both in the breeding
season and in winter. This was to have begun in 1997 but
details of the winter protocol are not known to me at
this time. The most well described winter atlas project
is that completed in the early 1980's for Great Britain.
It is this Atlas which serves as the model for the
current effort in Ohio. If you wish to view a copy here
is the publisher's information:
TITLE: Atlas of Wintering Birds in Britain & Ireland
ISBN: 0856610437
Publisher: Poyser, T. & A. D. Limited
Publish Date: 01/01/1990 (Originally published in 1986 -
VF)
Compiled by: Peter Lack
Binding: Hardcover , 352 pages
List Price: USD 41.00
What is an Atlas Block?
The block is the unit of area for which a separate
checklist is generated. It is a 7.5 minute quadrangle.
This universal map unit affords a convenient size area
for birding coverage. Quadrangles can be obtained
individually from the State of Ohio though the Ohio
geological Survey. Far simpler, is to reference the
Delorme Atlas & Gazetteer. This road atlas is available
at retail stores. The quadrangle is defined within this
publication by very fine cross-hairs. These can be very
difficult to see amidst the map symbols and line so
consult a page including a portion of Lake Erie where
the marks are more visible. Using a straight-edge, draw
lines connecting the cross-hairs in order to define your
particular block.
Why just January?
The aim here is to obtain a data set by which land
managers may have reasonable confidence in identifying
the wintering species in a particular area of the state.
In Ohio, a great deal of the water birds (from ducks to
gulls) are still on the move in December. In recent
years, 50% of the Sandhill Crane flight has taken place
in December. Similarly, spring migration is normally
underway by 10 February with the arrival of blackbirds,
and the first waves of Turkey Vulture, Killdeer, and
American Woodcock. In early springs, waterfowl,
especially Northern Pintails and Green-winged Teal are
widespread and common arrivals the first few days of
February. Among songbirds, Horned Larks and Snow
Buntings are frequently on the move at this time.
What is the difference between a winter Visitor vs. a
winter Resident?
In addition to determining presence/absence of a species
(generating a simple map of distribution), this survey
aims to map the maximum concentrations of each species
by order-of-magnitude (e.g. X, XX, XXX, etc.), and it
will attempt to distinguish between Visitors vs.
Residents. The need for the latter recognizes that
although this survey is restricted to the heart of the
winter season, several species are still on the move
during this period. Rather than ask the general public
to try to make the very difficult determination of what
is a migrant vs. a bird intent on over-wintering, this
survey opts to define sightings as visitors and
residents. The distinction between the two is
arbitrarily set at 16 days. Should a species be recorded
16 days apart within the recording period, it can be
said to have been present during the majority of that
period. Hopefully, this will serve to distinguish brief
visits by migrants still passing through the state,
while also separating out those very rare winter
visitors not normally a part of the Ohio winter
birdlife. This definition also serves to avoid
subjective a priori assumptions as to what species are
normally a part of the Ohio winter birdlife.
Of the three types of information gathered during this
survey, this may well prove to be the most challenging.
Example from 2002: Two visits were made to Kelleys
Island, the principal land mass within grid 28D4. The
visits on 12 and 28 January were 16 days apart. The 2nd
visit recorded 38 species, including 4 that were missed
on the first visit. In turn the late season visit missed
12 species recorded on the first visit. Therefore only
68% of the total species recorded in 28D4 were verified
as Resident. In future seasons, the remaining unverified
species will be the target of a little more effort in
order to verify as high a percentage as possible as
winter residents.
Why not count birds passing over the grid?
The Ohio Winter Bird Atlas follows this rule as stated
in the British Bird Atlas.
"Observers were asked to record only birds USING the
square. 'Use' of the square included feeding, resting,
or roosting, Flying birds were recorded where the birds
were obviously using the habitat within the square; for
example, hunting raptors or movement from one copse to
the next, but birds simply flying over the square were
not included."
What does one want to say with the data from a winter
bird atlas or any atlas? It is my philosophical
position that such surveys need be of value in assessing
the importance of the area surveyed. USAGE of the area
therefore is critical. A SIDE-EFFECT of this criteria
would be to fine-tune the survey further with regard to
the elimination of potential migrants. However, it is
not the justification for doing so. As has been pointed
out, Sandhill Cranes in a field would count because of
their use of the land while hundreds of high-flying
migrants over other Atlas Blocks would go unrecorded.
That aspect of their status is already dealt with by the
criteria identifying resident vs. visitor (see above).
USAGE gets most directly to the task of assigning
ornithological value to an area. And it is this value
that this survey is intended to reveal during a time
period for which virtually no coordinated information
exists for the state of Ohio.
So where does one draw the line? One must ask
whether the bird flying over the area is merely trying
to get to another grid? Two questions, two sides of the
same coin, one should ask when seeing a high flying bird
are:
Regardless of its surroundings, would the bird be
passing over the area as it is doing so?
Ask whether the bird is responding in flight to the
local habitat vs. the topography?
A kingfisher flying up a stream, a Peregrine over an
office building, harriers, kestrels, etc. hovering over
a field are all interacting with the local environment
therefore USING the area. Some of these are judgment
calls admittedly, but migrants are virtually always well
above (2 or 3 time) tree-top height or building height
when in the act of flying over an area. Whether
migrating or traveling a distance to forage at a
specific site (e.g. gulls at a landfill), the birds
collectively will also pass over in a very direct
manner. Where small deviations from level flight is
common in local birds (presumably for predator
avoidance) such deviations are exceptional in migrants
overhead, where such deviations cost too much of the
energy stored up for the flight. Such birds traveling
over an Atlas Block rarely respond to habitat-level
features of the landscape but may use larger grain
features such as lake shores or escarpments. A bird
following a hedge row, tree line, stream corridor, or
some other habitat-level feature is making use of the
local environment and therefore to be counted on the
Atlas.
Birders can expect that 99.9% of what they see in
January to be birds using the local landscape. Here are
some troublesome species:
t
Late fall migration of
mergansers and other diving ducks on Lake Erie; the
confusion here is with birds merely engaged in foraging
flights. Careful observation should reveal these birds
will be seen resting, even if momentarily, on the Lake
and therefore counted.
t
Late fall migration of
puddle ducks in the northwest; especially the Sandusky
River Corridor; generally between 200-400 ft overhead.
late fall migration of Sandhill Cranes over the western
third of the state.
roost movements of crows, blackbirds, robins, starlings;
although likely not so far as skip over an entire block.
t
Daily foraging flight of
gulls off Lake Erie to inland fields and landfills;
typically birds seen passing over between 200-400 ft.
t
Early spring flights of
crow, Snow Bunting, and Horned Larks along the shoreline
of Lake Erie; careful observation will almost always
reveal individuals stopping to rest momentarily during
passage thereby countable on the census.
These observations, were they included in the greater
data set would lessen the integrity of the data
regarding what it may say of the use of habitat in Ohio
by birds during the winter season. The object is not to
obtain complete species lists based merely upon
presence, but to list those species USING the area being
surveyed in the manner identified by that survey. A bird
passing over a grid merely to get to another grid
implies nothing of the value the habitat within that
grid may possess. Whereas a bird USING that grid does
imply something - exactly what may not be known but
first things first.
The Role of Anchor Points
I am looking for individuals who will be able to commit
to the minimum of 16 hrs of observation (four 4-hour
days) through the month of January for one or more of
the 60 specific blocks that are listed. If necessary,
two or more people may share the responsibility of that
minimum effort. The aim here is to be able to ascertain
through a consistent effort what will hopefully be 90%
or better of the species potential for these blocks.
That way we can see how the effort in the other 700
blocks measures up, and consequently identify those
blocks that may require a bit of extra effort toward the
end of the project.
In the northern tier of blocks, we may learn that 70
species is a fairly consistent occupancy rate of those
blocks. Therefore, when after 2-3 years we see several
adjacent blocks at half that number, we know to lavish
some additional attention on those blocks to bring them
up to snuff.
Coverage of non-Anchor blocks
Anyone may cover whatever area they wish, however they
wish to cover it. The goal with any block is to generate
as complete a checklist of species as possible.
Duplication of some effort will be necessary for
detecting Residents vs. Visitors. However, initially the
focus should be on fleshing out the species list. Just
go out and bird and send in your results. I encourage
birders to bird as they would normally, only be
cognizant of the block within which you are observing
the birds. hopefully, this project will bring an
awareness of certain corners of your home territory,
presently receiving very little coverage, causing you to
visit sites you otherwise would not. Once the species
list appears to be fleshed out, your focus should shift
to upgrading the maximum concentration that species is
recorded in the block. Perhaps the most difficult aspect
of the survey will be the focus of the final stages of
data collection, that of verifying as many of the
species as Resident vs. Visitor.
Approaches to birding a block vary. The local extreme
may be merely a matter of minding only that which passes
through one's yard or local park. At the other extreme,
you may find yourself driving through 5 grids to get to
a particular birding location. Birds by the side of the
road would generate a checklist for each grid. Either
approach is equally useful to this project.
How frequent should one visit? It is hoped that
Anchor Block data will shed some light on this question.
Until then, should the season be the first in which the
block is being visited, aim for making a half-dozen
visits to each of two blocks, or ideally 3 blocks
visited four times (once per week) over the month of
January. Blocks especially diverse in habitat will
likely requires 4-6 hrs of coverage on each of 4
visits/month. Blocks where a single vegetation type
dominates, especially in heavily agricultural areas,
will likely see little change to the species list after
two such intensive visits.
Grid References
The block is referenced by the Page and number and
letter in the margins of the page. Most every page
references 28 blocks A through D and 1 through 7.
Question: Column 4 on each set of facing pages
spans those pages. Do we report separately for the two
pages, e.g. 74A4 and 75A4? Or do we combine them into
74-75A4?
Answer: Report the combination 74-75A4.
Question: When a block is only partially in Ohio,
do we report only for the Ohio portion of the block.
Answer: Yes.
Question: In some cases, such as 74D1, the
portion in Ohio will be quite small. Should we still
report separately for such a small area, or would there
ever be a case where you would want us to lump it into
the adjoining block?
Answer: Do not lump blocks. Each block gets its
own checklist of birds.
Some stats for the curious. Virtually all blocks
bordering MI, IN, and PA have Ohio as the major portion
of the block. There are 79 blocks involving the Ohio
River. Of these, only 10 have a total area occupied by
Ohio of 1/6th or less (one-sixth of a quadrangle was the
size of the reporting block used in the Ohio Breeding
Bird Atlas).
Last updated on
Monday, January 25, 2010 |
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