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Upper Midwest Environmental Sciences Center

Maps, Models, and Tools for Bird Conservation Planning

Modeling Avian Abundance: Results - Bobolink

These results are available in:
Thogmartin, W. E., M. G. Knutson, and J. R. Sauer. 2006. Predicting regional abundance of rare grassland birds with a hierarchical spatial count model. Condor 108:25-46.

Modeling Avian Abundance: Results
  Avian Species-of-Concern in the Prairie-Hardwood Transition Ecoregion (Bird Conservation Region 23)

Bobolink
Dolichonyx oryzivorus

 

Conservation Estate Portfolio for the Bobolink (Dolichonyx oryzivorus)

Bobolink Predicted Relative Abundance Map


Bobolink Predicted Relative Abuundance (map - click for larger scale)

Bobolink

Bobolink

AOU Code BOBO
Habitat Association grassland
Nest Type and Location open-cup, ground/low
Migration Status Neotropical
Conservation Score 23

Bobolink Predicted Relative Abundance Map
This map indicates predicted relative species abundance. The predicted count of any cell in the map represents the expected count if a Breeding Bird Survey route were centered on that cell.

Bobolink Predicted  Relative  Abundance Map

 

Bobolink Averaged Habitat Model

Explanatory Variable Scale (m) Median 95% LCL 95% UCL Variable Importance
Area-weighted Grass Patch Size (m)
100
-0.017
-0.021
-0.012
0.576
Area-weighted Grass Patch Size (m)
1,000
0.321
0.317
0.326
0.283
Total Forest Composition (%)
100
-0.542
-0.547
-0.536
0.329
Total Forest Composition (%)
1,000
-0.539
-0.544
-0.533
0.424
Total Forest Composition (%)
10,000
-0.371
-0.378
-0.364
0.247
Temperature During the Coldest Quarter
 
-0.877
-0.894
-0.860
1
Coefficient of Variation in Annual Precipitation
 
-1.146
-1.171
-1.121
0.141
Grass Patch Size and Forest Composition
1,000
0.292
0.287
0.297
0.859
Area-weighted Mean Grass Patch Shape
1,000
0.309
0.310
0.308
0.576
Coefficient of Variation in Grass Patch Contiguity
1,000
-0.386
-0.391
-0.381
0.671
Spatial CAR
 
1.175
1.170
1.179
1

K-L Best Subset Models

Model Explanatory Variable Scale Parameters DIC ΔDIC wi Evidence Ratios
1
Grassland Patch Size100, Forest100, Temperature During Coldest Quarter, Grass-Forest Interaction, Grass Patch Shape1,000
1074.67
9153.83
0
0.329
1
2
Grassland Patch Size1,000, Forest1,000, Temperature During Coldest Quarter, Grass-Forest Interaction, Grass Patch Contiguity1,000
1077.25
9154.13
0.30
0.283
1.16
3
Grassland Patch Size100, Forest10,000, Temperature During Coldest Quarter, Grass-Forest Interaction, Grass Patch Shape1,000, Grass Patch Contiguity1,000
1076.67
9154.40
0.57
0.247
4
Forest1,000, Temperature During Coldest Quarter, CV Precipitation, Grass Patch Contiguity1,000
1077.68
1.69
0.141
2.33
NULL
 
1520.29
9621.41
467.58
9.6E-103
3.4E+101
Parameters: Effective number of parameters
DIC: Deviance Information Criterion
ΔDIC: Difference in deviance between model and best model
wi: Model weight
Evidence Ratio: Ratio of model i relative to the best model
 

Bobolink Population Trend Graph

Bobolink Population Trend Graph


*
Partners-in-Flight Conservation score for PIF16

(171 KB .pdf file - requires Acrobat Reader)  

Scores range between 5 and 35, with higher scores signifying greater conservation concern. Each species is of management concern because of their rarity, declining abundance, or habitat specificity (http://www.blm.gov/wildlife/pl_16sum.htm).

Content manager: Wayne Thogmartin

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