The first items in each account are the species' common
and scientific names, for which we follow the seventh
edition of the
Check-list of North American Birds (American Ornithologists' Union 1998 and updates
through the 50th supplement), and the species number
from The North American Bird Banding Manual (Gustafson et al. 1997).
The encounter map shows lines joining banding
locations with encounter sites for birds encountered
more than 100 km from the banding site. The symbol
at the end of each line marks the encounter location.
Prior to mapping, data were screened to delete
records showing encounters within 100 km of the
banding site (the latter being relatively uninteresting
for depiction on maps). Encounters with inexact
location codes or coordinates were also excluded,
except as follows. Records providing degrees of
latitude and longitude but lacking the exact 10' block
were assigned coordinates at the southeast corner of
the 1o block. Some of the older encounters from
Mexico report the state but do not give any
coordinates; in such cases, we assigned coordinates for
the centre of the state. To ensure that scarce longdistance
encounters would be mapped, we also
assigned coordinates for inexact locations within
Central or South American countries, giving
coordinates for the centre of the relevant country.
For species with few band encounters, every
record of movement greater than 100 km could be
mapped individually. However, this was not possible
for species with high numbers of encounters, as even
maps with as few as 50 lines can appear too cluttered.
We therefore reduced the complexity of the maps using
several methods. For example, for a few species (noted
in the text), we omitted encounters within 200–400 km
of the banding site, as opposed to the usual 100 km. A
second approach was to produce several maps for a
species to allow depiction of more cases.
Most commonly, we used a thinning process.
First, groups of records were identified that shared the
same banding and encounter coordinates (i.e., all the
birds were banded within one 10' latitude-longitude
block and encountered within another 10' block). Then
a single line was plotted with a larger symbol to
indicate the number of encounters represented by that
line (see key on each map). If further thinning was
required, coordinates were rounded to form larger
degree blocks (instead of 10' blocks), and new (larger)
groups of records were formed that shared the new
banding and encounter coordinates. From each group,
a single record was randomly chosen to represent the
group on the map, and these lines were plotted using
their original coordinates. Again, the size of the
symbol at the end of the selected line shows the
number of records represented. If the map was still too
crowded, the process was repeated with larger block
sizes until the maps became clear. Block size in
degrees (in decimal format) is shown with each map
for which block size was enlarged above 10' of latitude
and longitude for the purposes of thinning.
The number of encounters represented by each
symbol is consistent across all maps, with only two
sets of frequency classes being used: one for large data
sets (map symbols are triangles) and one for smaller
data sets (map symbols are squares).
The result of the thinning process is a set of lines
joining banding and encounter locations that
summarizes geographic patterns of movement, rather
than showing every encounter separately. The
advantage of this system is that sparse or outlier
records are not eliminated in the thinning process,
whereas dense areas of repetitious records are
rigorously weeded to reduce clutter. The disadvantage
is that many individual records (sometimes hundreds)
are not shown on the maps. When block size is large
(over a few degrees), the text draws attention to that
fact and notes any distortions of pattern that may
Each narrative begins with a clarification of taxonomy
if taxa traditionally recognized by banders do not
coincide with those in current use by systematists. A
short description of the North American breeding
distribution and each species' wintering area follows,
based mainly on Peterson (1980), the American
Ornithologists’ Union (1998 and subsequent
supplements), Godfrey (1986), and individual species
accounts in the Birds of North America series (Gill and
The main body of the text discusses movement
patterns revealed by the encounters and refers to
specific records (by number) that are listed below the
text. If there are major published analyses of band
encounters for the species, relevant results are
summarized briefly in the account, even if published
later than the cut-off date for including band
encounters (end of 1995). Cited longevity records
(from the U.S. Banding Laboratory web site) were
current as of 2006.
The encounter records are listed in a standard format.
Each one occupies two lines, the upper containing
mostly the banding information, and the lower, the
encounter details. The band number is given first.
Below it, on the second line, appear either the initials
of the bander or, if these cannot be traced, the bander’s
permit number or acronym of the permitting
organization or the name of the country of banding.
(This is the only banding information that appears on
the second line rather than the first.) The name of the bander can be displayed by scrolling over the bander’s initials.
All codes in the encounter listings are from The North American Bird Banding Manual (Gustafson et al. 1997). The meaning of the codes can be displayed by scrolling over the code. These codes are used
in preference to the “international” symbols because
they contain more information (Brewer and Salvadori
1978). Following the band number and the initials or
permit number of the bander or country of banding are
two sets of codes: on the upper line, the alphabetic
versions of the codes for age (first) and sex (second) of
the bird at banding; on the lower line, the numeric
codes for “present status of bird and band” and “how
obtained” from the encounter data. Together, the latter
two codes give some indication of the completeness of
information for the particular record.
Next are the dates of banding (above) and
encounter (below). Note that these are in the order
day/month/year (not month/day/year as they are in the
computer files), to conform with common Canadian
usage. Special codes indicate inexact dates of encounter (an explanation is provided by scrolling over the code).
Dates are followed by the names of the places of
banding (above) and encounter (below). Most place
names were obtained from the gazetteer of banding
and encounter localities on file at the U.S. Bird
Banding Laboratory. The location names in the
gazetteer were assigned by Laboratory personnel and
frequently differ from the names that banders assign to
their own sites. We have changed site names to those
more recognizable by banders in the few cases where
we knew which names were more appropriate, but in
many cases we were not able to do so. When locations
were not given in the gazetteer, we used atlases to find
nearby place names.
The next data in the encounter records are the
latitude and longitude of banding (upper line) and
encounter (lower line), expressed as the coordinates of
the southeast corner of the appropriate 10′ geographic
block (Gustafson et al. 1997). Question marks indicate
inexact locations. Where we assigned coordinates (see
notes in section 4.2), the distance travelled (see below)
is given as approximate. In a few specific cases for
which revelation of the breeding locations might be
deleterious to the bird, precise banding locations have
been omitted. In these cases, we have identified only
the province or state and rounded the geographic
coordinates and the distances travelled.
The last data given are not extracted from the
standard computer files but have been calculated
separately. On the upper line is the time elapsed
between banding and encounter (omitted when date of
actual encounter was ambiguous or the bird was long
dead at the time it was found), and on the lower is the
calculated distance and direction between banding and
encounter locations (see
Additional details on data coding and analyses).
The latter is
blank when locations are inexact or where approximate
locations were assigned (see section 4.2), in which
case approximate distance and direction were
calculated. Most encounters listed in detail are
specifically cited in the text, but often the bird with the
longest period between banding and encounter is listed
at the end without any comment.
A summary of banding statistics is provided for each
species with bandings in Canada. Data are arranged in
three columns: birds banded in their first calendar year
of life (Hatch Year), those banded in their second or
subsequent calendar year of life (After Hatch Year),
and the total banded regardless of age (including birds
of unknown age when banded). An explanation of each
line in the summary table is given below.
No. of Canadian bandings (1955-1995):
Banding numbers were not handled by computer
prior to 1955, so this item and the next ("No.
encountered per 1000 banded") are restricted to the
1955–1995 period. These two lines are italicized in the table to emphasize that they are a restricted subset of the numbers appearing in the remainder of the table. The term Hatching Year refers to birds banded in the calendar year of hatching; After Hatch Year includes all older birds. Note that the Total also includes birds of unknown age.
No. encountered per 1000 banded (1955-1995):
The number of encounters includes birds killed,
found dead, or captured alive, as well as sight records
(i.e., bands read from a distance). If a single bird was
encountered multiple times, it was tallied only once.
The encounter rate is influenced by such factors
as the size and conspicuousness of a species, density of
human population, and whether the species is hunted,
as well as by the geographic distribution of bird
banders and the number of individuals of the species
they handle. The encounter rate is also affected by the
number of reports of birds encountered in the same 10′
block in which they were banded. Prior to 1958,
encounters within 90 days at the site of banding were
incorporated into the database (although the numbers
are not large); in 1958, however, this practice was
discontinued. Encounters at the site of banding more
than 90 days after banding can still be submitted to the
banding office; however, some banders do not submit
such encounters, and not all of those sent in are
actually entered into the database (L. Métras, pers.
Total no. encountered (1921-1995):
No. of encounters of birds banded in Canada
(1921–1995) + no. of Canadian encounters of
birds banded elsewhere (1921–1995)
All further calculations in this table are based on
this set of encounters. Duplicate encounters of the
same bird were excluded.
No. encountered from foreign bandings:
No. of the above encounters (1921-1995) that involved birds banded in another
country but encountered in Canada
Maximum period from banding to encounter (mo.):
Maximum for any individual, rounded to the nearest month
This information is provided as an indicator of a
bird's minimum age, so is not provided when date of
encounter or actual date of death is highly uncertain.
Note also that this figure does not represent longevity,
except for birds banded as very young chicks, as no
attempt was made to estimate the true age of the bird
by guessing at its age when banded.
No. of Canadian-banded birds moving > 0 km:
This number gives the sample size for the calculation below.
Mean movement > 0 km of Canadian-banded birds:
The distance between the banding and encounter
locations of each record was computed using a
great-circle distance — that is, the shortest distance
that could be travelled between the two coordinates
allowing for the curvature of the earth (Cowardin 1977;
Additional details on data coding and analyses).
Although the maps show straight lines
connecting points of banding and encounter, no birds
are likely to fly in an exact straight line, least of all
seabirds, most of which will not overfly land and
hence are constrained by the shape of coastlines. This
is particularly important to bear in mind when
considering birds banded in Hudson Bay or the Gulf of
St. Lawrence and encountered on the U.S. east coast.
These individuals must have travelled much farther
than the straight-line distances suggest. Hence, mean
movement should be treated as the absolute minimum
distance that individuals had travelled between
banding and encounter. Distance travelled is shown as
approximate in records for which we assigned
encounter coordinates (see explanation in section 4.2).
Maximum movement from all encounters (km):
Maximum calculated distance moved for any
Unlike the calculation for mean movement of
Canadian-banded birds (above), the maximum distance
is given for any encounter in the database, regardless
of banding location.
% recovered (encountered dead):
Birds with "unknown" present condition codes were treated as dead for this
calculation and the next one ("% direct recoveries"), as
were birds banded in their Hatch Year and encountered
in the same 10' block within three months of banding.
Birds encountered before 1965 and birds banded
outside the North American banding scheme (mainly in
Europe and Greenland) did not have true "present
condition" codes to indicate whether the encountered
bird was alive or dead. We assigned codes to these
records based on available information to enable their
inclusion in this calculation.
% direct recoveries:
A direct recovery is an encounter with a bird
"killed or found dead before, during, or immediately
after the first period of migratory movement following
banding and before return migration would be likely to
have occurred" (Gustafson et al. 1997).
Additional details on data coding and analyses
shows how this designation was assigned; see also
notes above on "% recovered."
The "% direct recoveries" is used chiefly as a
measure of the hunting pressure on species in which
most of the mortality is inflicted by hunters. In species
that are not hunted, this figure is a rough guide to the
magnitude of annual mortality. In the majority of
species, this figure will be much higher for birds
banded in their Hatch Year than for those banded in
later years, reflecting the high mortality of juveniles
typical of most birds.
% encountered during banding operations:
The number of birds encountered during banding
operations was the sum of birds with "how obtained"
codes of 89 or 99.
The banding effort map shows the numbers of
individuals for each species that were banded in
Canada from 1955 to 1995 in each location (compiled
by 10′ block, with blocks combined if too close to be
shown separately on the map). This map helps the
reader interpret the distribution of encounters, because
it shows where banding effort has been concentrated.
Under each map is a list of up to five of the master
Canadian permit holders responsible for the most
bandings of the species in Canada from 1955 to 1995
(listed in descending order). One to many individuals
may band under a single master permit, so this listing
does not necessarily identify the most prolific