COMMON GRACKLE

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Common Grackle
Copyright © 2005 Eric Secker

 Conservation Concern: NONE

Population Trend: Substantial Increase
 Credibility: Good

Common Grackle Description.  Preferred habitats include open shrublands, forest edges, and marshland edges with shrubs.  BCN eBird data indicates a substantial increase since 1997.  Populations in urban areas and agricultural areas are poorly represented by BCN Census point counts which are usually located in preserved areas.

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*:		  
  12%   ----  
   
   

 

 

Technical Notes (1997-2004 Trend)

Sample Size (Indiv.): 1297

Sample Size (Records): 416

 

AVG. YEARLY RATE OF CHANGE:
(including standard error)
3 to 22

  GOODNESS OF FIT:
Chi-square: 950.71, df 452, p 0
Likelihood Ratio: 922.63, df 452, p 0
AIC: 18.63
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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