Field Notes Journal

Seasonal Analysis and Species Classification

Great Crested Grebe

Model Family : Resident detectability

Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK David Walker, Field Notes Journal ( CC BY 4.0 )
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK David Walker, Field Notes Journal ( CC BY 4.0 )
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK David Walker, Field Notes Journal ( CC BY 4.0 )
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK
Great Crested Grebe (Podiceps cristatus), Radley Lakes, UK David Walker, Field Notes Journal ( CC BY 4.0 )
Great Crested Grebe (Podiceps cristatus), Farmoor Reservoir, UK
Great Crested Grebe (Podiceps cristatus), Farmoor Reservoir, UK David Walker, Field Notes Journal ( CC BY 4.0 )

Summary

Great Crested Grebe

Resident with summer detectability collapse

Great Crested Grebe is classified as resident with summer detectability collapse. The fitted resident detectability target peaks around April and reaches its lowest point around September. The model indicates moderate baseline presence, weak spring carry-over, moderate pre-summer retention, moderate summer suppression, and moderate summer decay acceleration.

Confidence
Medium
Fit score
0.224
Peak detectability
April
Lowest detectability
September

Seasonal wheel

Seasonal wheel for Great Crested Grebe Great Crested Grebe Peak: April

Calendar strip

Jan 0.31
Feb 0.36
Mar 0.61
Apr 0.76
May 0.46
Jun 0.31
Jul 0.29
Aug 0.26
Sep 0.18
Oct 0.2
Nov 0.26
Dec 0.37

Highlighted months indicate stronger modelled presence or detectability. A ring marks the fitted peak; a hollow mark indicates the trough where available.

Classification evidence

Target peak month
4
Target peak label
April
Target trough month
9
Target trough label
September
Target peak value
0.764
Target trough value
0.177
Target mean value
0.364
Target amplitude
0.586
Baseline to peak ratio
0.337
Autumn to winter weight ratio
0.043
Year end to winter weight ratio
0.294
Decay to growth ratio
1.655

Observed and Simulated Seasonal Patterns

Great Crested Grebe Observed Presence, Thrupp Lake
Great Crested Grebe Observed Presence, Thrupp Lake
Great Crested Grebe Observed Totals, Thrupp Lake
Great Crested Grebe Observed Totals, Thrupp Lake
Great Crested Grebe Simulated Presence, Thrupp Lake
Great Crested Grebe Simulated Presence, Thrupp Lake

Cite this dataset

You are welcome to reuse or reproduce this material under the terms of the Creative Commons CC BY 4.0 licence but please cite it using the reference below, include a link to the licence, and indicate if any changes were made.

Walker, David. Great Crested Grebe. Field Notes Journal. ID FN-WL-SEASONAL. Version 2026.05.26. https://fieldnotesjournal.uk/wildlife/seasonal/thrupp_lake/great_crested_grebe.html

Dataset FN-WL-SEASONAL Author David Walker Publisher Field Notes Journal Version 2026.05.26
Reference: Walker, David. Great Crested Grebe. Field Notes Journal. ID FN-WL-SEASONAL. Version 2026.05.26.

BibTeX 
@dataset{fn_wl_seasonal,
  author = {Walker, David},
  title = {Great Crested Grebe},
  year = {2026},
  publisher = {Field Notes Journal},
  version = {2026.05.26},
  url = {https://fieldnotesjournal.uk/wildlife/seasonal/thrupp_lake/great_crested_grebe.html}
}