Listed below are the estimated North American population trends for House
Sparrows for both summer and winter populations. Data came from the North
American Breeding Bird Survey (BBS) (1966-1993) and the Christmas Bird Count
(CBC) (1959-1988).

My interpretation of Trends

Who would have guessed that House Sparrows would have declined so significantly
and with such geographic consistency during the past few decades? This common
and well-sampled species has logged significant declines in almost every region.
From BBS data the only exception to negative trends among the states and
provinces is Wyoming and with CBC data, Manitoba and Vermont. House Sparrows
are permanent residents so it is interesting to note that while the CBC shows
significant increases in Manitoba the BBS shows significant declines. This
discrepancy might be due to differences in the sampling time periods, or it
could indicate a sampling bias. The BBS tends to be a better representation of
the landscape as a whole, so my guess is that the CBC trends are more likely to
be biased.

Now, why would there be fewer House Sparrows around? House Sparrows and people
go together like erosion and water and there are certainly more people now than
30 years ago. Perhaps nest sites are now limiting. Builders are savvy enough
that homes are designed without the nooks and crannies for nesting that older
homes generally have. Bird house builders often use designs that minimize house
sparrow occupation. Food wouldn't appear limiting in cities; feeding birds is
as popular as ever. However, in farm operations, it may be that waste grain is
less readily available, through increased vigilance, better storage facilities,
or the combination of both numerically fewer farmsteads and those farmstead
keeping fewer chickens, pigs, goats, and other livestock. Looking at
physiographic regions, it is interesting to note that the Central Valley of
California, the Intermountain Grasslands, and the Glaciated Missouri Plateau all
had significant increases.

Perhaps there is something more insidious driving these trends...we can only
hope.

BBS trends (1966-1993)

Name Annual Trend sig. n rel. abundance
ALABAMA -4.625 *** 58 33.59
ALBERTA 1.287 53 32.30
ARIZONA 0.272 41 19.24
ARKANSAS -4.477 *** 31 39.50
BRITISH COLUMBIA -4.551 *** 34 4.94
CALIFORNIA 0.913 * 156 35.73
COLORADO -3.798 52 26.52
CONNECTICUT -0.477 17 26.65
DELAWARE -5.421 *** 10 78.44
FLORIDA -5.585 *** 69 10.31
GEORGIA -8.035 *** 60 18.17
IDAHO -4.558 29 25.21
ILLINOIS -1.534 *** 64 214.82
INDIANA -3.094 *** 42 157.15
IOWA -0.662 * 34 182.96
KANSAS -2.491 *** 39 82.14
KENTUCKY -1.769 ** 45 61.59
LOUISIANA -5.592 *** 44 30.15
MAINE -4.792 * 46 2.86
MANITOBA -2.870 *** 29 22.06
MARYLAND -4.060 *** 59 69.62
MASSACHUSETTS -0.285 23 30.24
MICHIGAN -2.272 *** 71 54.93
MINNESOTA 1.040 47 39.51
MISSISSIPPI -3.315 * 32 18.92
MISSOURI -3.564 *** 45 82.85
MONTANA -2.053 42 8.07
NEBRASKA -0.628 40 58.04
NEVADA -2.740 15 8.42
NEW BRUNSWICK -5.777 *** 26 15.05
NEW HAMPSHIRE 0.978 22 7.88
NEW JERSEY -4.598 *** 35 35.24
NEW MEXICO 3.032 43 8.80
NEW YORK -1.604 *** 113 36.16
NORTH CAROLINA -3.718 *** 44 37.42
NORTH DAKOTA 2.481 ** 46 48.85
NOVA SCOTIA -2.104 *** 24 10.16
OHIO -3.153 *** 65 139.54
OKLAHOMA -2.608 *** 55 36.55
ONTARIO -2.224 *** 66 9.10
OREGON -1.542 48 9.30
PENNSYLVANIA -3.007 *** 114 40.62
QUEBEC -2.232 ** 53 5.85
SASKATCHEWAN -2.404 *** 55 60.10
SOUTH CAROLINA -4.637 *** 23 27.23
SOUTH DAKOTA -0.702 39 24.94
TENNESSEE -0.603 43 27.81
TEXAS -2.065 *** 117 69.50
UTAH -2.533 24 14.95
VERMONT 1.762 24 16.95
VIRGINIA -4.556 *** 51 26.05
WASHINGTON -3.881 ** 41 28.68
WEST VIRGINIA -3.756 *** 41 20.37
WISCONSIN -0.524 69 92.72
WYOMING 8.336 * 48 7.65
FLORIDIAN -5.535 *** 28 12.11
COASTAL FLATWOOD -4.396 *** 77 16.22
U COASTAL PLAIN -5.445 *** 222 25.63
MS ALLUVIAL PLAI -5.059 *** 33 70.42
COASTAL PRAIRIES -5.878 *** 19 55.37
S TX BRUSHLANDS -1.120 *** 18 156.70
E TEXAS PRAIRIES -4.627 ** 22 65.26
N PIEDMONT -3.212 *** 45 68.22
S PIEDMONT -3.850 *** 61 21.35
S NEW ENGLAND -0.766 47 28.76
RIDGE AND VALLEY -2.454 *** 105 41.76
HIGHLAND RIM -1.238 * 54 60.04
LEXINGTON PLAIN -3.762 *** 25 111.07
GREAT LAKES PLAI -1.978 *** 92 138.03
DRIFTLESS AREA -0.526 24 164.25
ST LAWRENCE R PL -0.681 52 45.57
OZARK-OUACHITA -2.492 *** 38 31.20
GREAT LAKES TRAN 0.528 52 27.26
CUMBERLAND PLATU -3.314 18 16.03
OHIO HILLS -3.850 *** 55 31.72
BLUE RIDGE MTNS -4.782 *** 12 7.99
ALLEGHENY PLATEA -2.074 *** 117 35.84
ADIRONDACK MTNS -6.866 *** 20 2.96
N NEW ENGLAND 1.519 50 10.96
N SPRUCE-HARDWOO -5.263 *** 195 6.63
CLOSED BOREAL FO -3.415 24 0.78
ASPEN PARKLANDS -2.555 *** 86 30.45
TILL PLAINS -1.990 *** 89 198.49
DISSECTED TILL P -0.896 *** 61 166.39
OSAGE PL-X TIMBE -3.254 *** 43 56.50
HIGH PLAINS BORD -1.108 40 68.59
ROLLING RED PRAI -3.726 *** 20 52.22
HIGH PLAINS -3.456 51 49.57
DRIFT PRAIRIE -0.155 55 49.11
GLACIATED MO PLT 4.693 *** 48 53.52
GREAT P ROUGHLAN 2.052 63 13.32
BLACK PRAIRIE 0.674 37 78.38
EDWARDS PLATEAU -2.866 ** 18 25.09
ROLLING RED PLAI -2.316 15 46.63
STAKED PLAINS -1.784 * 17 120.49
CHIHUAHUAN DESER 3.599 26 9.61
CENTRAL ROCKIES -6.858 *** 30 1.40
DISSECTED ROCKIE -4.787 ** 34 8.45
GREAT BASIN DESE -7.022 15 19.66
SONORAN DESERT -0.058 26 65.15
MOJAVE DESERT -0.340 17 18.27
P-J WOODLANDS -3.919 ** 27 10.50
PITT-KLAMATH PLT -1.260 21 11.33
WYOMING BASIN 11.780 21 7.31
INTERMTN GRASSLA 4.095 * 37 6.54
BASIN AND RANGE -3.390 23 9.83
COLUMBIA PLATEAU -3.251 43 45.35
S CA GRASSLANDS -2.734 15 52.02
CENTRAL VALLEY 2.176 ** 25 109.78
CA FOOTHILLS -0.023 46 20.65
S. PACIFIC RAINF 2.903 * 44 4.99
N PACIFIC RAINFO -2.725 15 10.97
EAST -2.251 *** 1426 37.18
CENTRAL -1.499 *** 624 60.07
WEST -1.010 * 615 19.68
FWS REGION 1 -0.180 289 22.58
FWS REGION 2 -1.856 *** 256 42.27
FWS REGION 3 -1.420 *** 437 112.72
FWS REGION 4 -3.712 *** 449 29.65
FWS REGION 5 -2.851 *** 560 28.86
FWS REGION 6 -1.498 ** 330 30.84
UNITED STATES -1.780 *** 2321 43.82
CANADA -2.209 *** 344 16.63
ENTIRE SURVEY -1.842 *** 2665 37.18


CBC (1959-1988)

name annual trend sig n rel. abundance
MARYLAND -3.6 *** 31 51.75
MANITOBA 4.4 * 14 321.69
MASSACHUSETTS -2.9 *** 34 88.62
MICHIGAN -1.8 ** 62 122.13
KENTUCKY -1.1 24 65.38
LOUISIANA -3.3 *** 23 23.89
MAINE -6.5 *** 32 28.89
KANSAS -1.1 39 8463.99
NEBRASKA -1.4 20 209.18
MONTANA 0.4 28 98.02
MISSOURI -0.8 37 212.97
MISSISSIPPI -4.7 *** 18 29.68
MINNESOTA -0.7 59 182.18
NEW BRUNSWICK -3.6 ** 15 110.06
CALIFORNIA -2.7 *** 136 56.27
COLORADO -0.6 40 122.08
BRITISH COLUMBIA -5.1 *** 40 25.02
ARKANSAS -1.3 21 161.18
ALBERTA -2.3 15 113.57
ARIZONA -8.5 ** 46 86.97
CONNECTICUT -1.9 ** 21 96.60
ILLINOIS -1.0 62 418.07
INDIANA -0.7 47 192.12
IDAHO -4.3 *** 19 198.04
GEORGIA -3.4 * 29 26.09
FLORIDA -4.1 *** 64 17.75
IOWA -1.3 31 384.41
ALABAMA -5.6 *** 23 49.86
TENNESSEE -2.3 ** 30 37.06
TEXAS -2.4 *** 123 131.39
SOUTH DAKOTA 0.8 15 224.32
SOUTH CAROLINA -7.1 *** 18 51.66
SASKATCHEWAN -1.0 16 351.94
UTAH -6.0 *** 17 145.04
VERMONT 1.7 ** 14 91.38
WISCONSIN -2.3 *** 71 287.01
WYOMING -0.5 20 119.25
WEST VIRGINIA -3.4 ** 21 60.47
WASHINGTON -3.7 36 106.63
VIRGINIA -2.7 ** 57 43.38
QUEBEC -0.7 28 32.43
NEW YORK -2.7 *** 81 92.99
NORTH CAROLINA -5.3 *** 54 37.95
NEW MEXICO -2.4 * 28 100.31
NEW JERSEY -4.5 *** 30 68.58
NEW HAMPSHIRE -1.7 18 57.65
NORTH DAKOTA 1.5 24 322.10
NOVA SCOTIA -2.2 24 67.68
OREGON 0.6 45 53.49
PENNSYLVANIA -3.8 *** 80 95.25
ONTARIO -3.1 * 100 66.76
OKLAHOMA -1.0 25 68.09
OHIO -1.3 ** 71 179.67
ENTIRE REGION -1.9 *** 2107 290.44


Interpreting the Trends Yourself

Each line represents an estimated trend for a different region. For the
Breeding Bird Survey trends are presented by state, province, physiographic
regions, Fish and Wildlife Regions, country, and the entire region. Christmas
Bird Count trends are presented by state, province, and for the entire region.

Trend values are presented as the percentage change in population size per year.
A positive value indicates a population increase, while a negative one denotes
a decline.

If you want to calculate the overall decline, use the following formula (this is
really just the formula for compound interest).

TREND = 100[((A/100)+1)^n)-1]

where:

A = the annual percentage change
n = the last year of the survey time period minus the first year (i.e., 27 for
the BBS and 29 for the CBC)

The trends presented here are imperfect representations of population trends.
Each trends comes with an associated sampling error. For some abundant, easy to
detect species sampling error is small while for uncommon species or those
difficult to count (e.g., flocking species) sampling error is large. As a guide
to significance of the trend we use statistical tests to determine how likely it
is that the trend we estimated is really different from zero or no trend in the
population. We use a 3-star system to indicate how confident we are that the
estimated trend is different from zero. One star (*) indicates that we are 90%
confident, two (**) 95%, and three (***) 99%.

For those of you who like to think about such things, the lack of stars or
statistical significance does not necessarily mean that the population is doing
fine, but could equally mean that the survey is a lousy measure of population
trend and doesn't have the power to detect changes in population. Factors such
as low sample size, large sampling error, sampling bias, and low relative
abundance all can lower our ability to detect trends in populations. While you
are mulling over the interpretations of these trends, consider some of the
factors that could influence the trend estimates.

Sample size is listed under the column heading "N" and indicates the number of
routes that went into the analysis for the BBS and the number of count circles
for the CBC.

Abundance figures for each of the estimates from the BBS are calculated as the
average number of birds detected per route in those physiographic strata where
the species occurs. Abundance on for the CBC regions are calculated the same
way, but the measure is given as birds per 100 observer hours.

If you are interested in information for other species, other time periods,
regional summaries, raw data, annual indices, annual reports, statistical
publications, maps of physiographic regions, or more detatailed analyses (e.g.,
estimates of the variance) you can contact Bruce Peterjohn at the Breeding Bird
Survey Office at 301-497-5841 or peterjohnb at mail.fws.gov. The manager of the
CBC database, Brett Hoover, can be reached at 301-497-5819 or
Hooverb at mail.fws.gov. I am also available to answer questions regarding
interpretation.

sam

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L L L L L L L

NBS, 1849 C St., MS 3660, Washington D.C. 20240
Sam Droege DROEGES at MAIL.FWS.GOV 202-482-3925

===========================

From: "m.j. nelson" <mnelson at JULIAN.UWO.CA>

I have an hypothesis for my own backyard. The decline in House Sparrow
numbers coincided with the arrival of the HOUSE FINCH about 10-12
years ago. I have no evidence of House Sparrow nesting in any
neighboring backyards or my own for at least 7-8 years, but there
are many House Finch nests.

| Michael J. Nelson
| Graduate School of Library
| & Information Science
| Elborn College email: mnelson at julian.uwo.ca
| University of Western Ontario
| London, Ontario, CANADA N6G 1H1

==============================

From: Sam Droege <droeges at MAIL.FWS.GOV>

There may be something to this, but, it wouldn't explain the
declines throughout the West and the slight tendency to decline
less steeply in New England.

sam
NBS, 1849 C St., MS 3660, Washington D.C. 20240
Sam Droege DROEGES at MAIL.FWS.GOV 202-482-3925

===================

From: Kay Annette Bristol <abristo at TENET.EDU>

It's hard to notice it here where about 100 (at least) house
sparrows come to eat and get water (just before sundown everyday).

ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
Annette Bristol S. TX
Internet - abristo at tenet.edu
K.Bristol at genie.geis.com
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz