AMERICAN CROW

American Crow
Copyright © 2005 Eric Secker

Conservation Concern: NONE

Population Trend: Substantial Decrease
Credibility: Good

This common statewide breeder took a newsworthy plunge due to West Nile Virus in recent years. 29 BCN eBird points sampled in both 2002 and 2003 had American Crow sightings during at least one of those years. The combined total for these 29 sites dropped from 43 in 2002 to 15 in 2003 - a decrease of over 65% in a one year period! However, the long term decline indicated by the data below may only be representative of preserved sites and does not accurately account for the many crows that breed in urban and agricultural areas which are insufficiently monitored.

Trend Level

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Avg. Yearly
Rate of Change:

The vertical axis numbers represent an index of the population change.

Note that the scales may vary between graphs.

Avg. Yearly
Rate of Change*:

-14%

-1%

Technical Notes (1997-2004 Trend)

Sample Size (Indiv.): 976

Sample Size (Records): 457

AVG. YEARLY RATE OF CHANGE:
(including standard error)
-20 to -9

GOODNESS OF FIT:
Chi-square: 955.14, df 593, p 0
Likelihood Ratio: 966.22, df 593, p 0
AIC: -219.78
NOTE: (model fits if p values are above 0.05)

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1997-2004 Trend Point Count Data	1988-2004 Trend* All Observation Types