RING-BILLED GULL

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Ring-billed Gull
Copyright © 2005 Eric Secker

Conservation Concern: NONE

Population Trend: Substantial Increase
Credibility: Mod. Good

The Ring-billed Gull is a very locally fairly common breeder in the CW Region.  Breeding habitat includes marshland islands and protected grassy areas near water.  Once absent as a nester in Illinois, the Ring-billed Gull has since established a number of large breeding colonies in the Chicago area.  Although this species is poorly sampled by the BCN Census, trend estimates still show a notable yearly increase.

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*:
 
  77%   1%  
   
   

 

 

Technical Notes (1997-2004 Trend)

Sample Size (Indiv.): 280

Sample Size (Records): 81

 

AVG. YEARLY RATE OF CHANGE:
(including standard error)
28 to 126

 GOODNESS OF FIT:
Chi-square: 236.98, df 88, p 0
Likelihood Ratio: 225.99, df 88, p 0
AIC: 49.99
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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