20 September 2011

What happened to the recoveries?

After looking at how many recoveries we get from predators in the last posting, I thought it would be nice to look at the recoveries we get as a whole.

I have used all the recoveries that we have received from August up until now. We use two codes to say what happened to the birds. The finding condition tells us, for example, if the bird was found dead or alive. The finding circumstances give the cause for what happened to the bird, if known.

The pie chart below is of the condition of the bird reported. As you can see the vast majority of reported birds are dead but a reasonably large slice goes to ringers catching birds after that have already been ringed (this generally only includes birds travelling more than 5km from the site of ringing).

The second pie chart is of the finding circumstances. We have a multitude of codes for the circumstances but I have just highlighted those that we have had more than 10 reports.

The 'bird found' slice is when the finder just finds the bird's body but doesn't know what happened to it. Obviously the pie chart results are very specific to this time of year and the proportions change very quickly. For example this is the start of the shooting season and we get a sudden increase in the number of birds shot compared with earlier in the year.

It should be pointed out that these portions are of reported individuals, for example you would hope that 100% of all shot birds would be reported but not all birds are reported that end up in a cat's belly.

No comments:

Post a Comment