BLUE JAY

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Blue Jay
Copyright © 2005 Eric Secker

Conservation Concern: NONE

Population Trend: Substantial Decrease
Credibility: Very Good

The Blue Jay is a common statewide breeder.  Blue Jays often nest in woodlands, mixed forests, or forest edges with mast-producing trees (usually oaks).  Nests may be placed in forks of trees or dense shrubs.  BCN eBird data indicates that this species has decreased significantly.  Also note, the significant drop between 2002 and 2003 which may be linked to the spread of West Nile Virus.

Trend Level

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

*Data gathered using a assortment of sampling methods  - for casual inferences only
  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*:
 
  -11%   -3%  
   
   

 

 

Technical Notes (1997-2004 Trend)

Sample Size (Indiv.): 786

Sample Size (Records): 505

 

AVG. YEARLY RATE OF CHANGE:
(including standard error)
-18 to -5

 GOODNESS OF FIT:
Chi-square: 514.88, df 486, p 0.1763
Likelihood Ratio: 531.91, df 486, p 0.0736
AIC: -440.09
NOTE: (model fits if p values are above 0.05)

Download Table of All Observations

 

 

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Copyright © 2005 Audubon - Chicago Region & Bird Conservation Network

 

 
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