Counting Coots

Not a sighting, but a general observation regarding coots.

The following two graphs provide numbers of Coots counted on Allen Pit (in Dorchester), and Thrupp/Bullfield Lakes (Radley Lakes). As can be seen in the graphs, there has been a significant and sudden unseasonal decline in Coots on these lakes over the last week.

 

In contrast, numbers of Coot on Farmoor Reservoir have increased. The graph below provides the number of Coot on Farmoor Reservoir recorded in 2022 during twice monthly counts (blue bars), and the average number recorded between 2018 and 2021 for comparison (red line). The graph highlights that far from Coots starting to decline on the Reservoir (as they typically do at this time of year), the number of Coots recorded at Farmoor today (1140 individuals) is broadly double that typically recorded at the end of October. Further, the count of 1140 individuals is the highest number I have recorded at Farmoor since commencing regular monitoring in 2013. Finally, to note, the majority of the individuals were on F2 (with 1.1% of Coots on F1). 

Based on the above, have Coots from Allen Pit and Thrupp/Bullfield Lakes moved to Farmoor? If so, why? Has the reduced water level at Farmoor increased its suitability for Coots? Further, how do Coots know to leave the lakes to move to the Reservoir? It is interesting to note that the majority of birds were on F2, with few on F1 when the water level was of a similar level (though I note today, the water level had risen on F1). Are the depths of F1 and F2 different to explain this pattern of occurrence, or could disturbance be implicated (i.e. paddleboards who typically paddle around the periphery of F1 and could flush Coots to F2). Finally, the combined numbers of Coot that have been ‘lost’ from Allen Pit and Thrupp/Bullfield Lakes (c150 individuals) do not equate to the increase in number on the reservoir, therefore are there any waterbody/waterbodies in Oxfordshire that have lost c370 Coots? 

Coots at Farmoor