Ed discusses the results of the 2024 tree sparrow nestbox monitoring.
The tree sparrow breeding season has ended with the last fledglings confirmed last Tuesday. It's sad to see it end but exciting that I now have a chance to look back over the data!
This spring and summer has had substantially more rain compared to the last few years when intensive monitoring has taken place. However, there has still been an increase in the population here at WWT Caerlaverock. We have had a total of 126 fledglings, a 27% increase from 2023. 58 of these were from the first brood, 63 from the second and 6 from the third. This year's third brood was disappointing to say the least but the heavy rain in August didn’t leave us much hope!
Furthermore, this year we had 21 successful boxes and 33 successful broods across the site. Only a maximum of 15 boxes produced fledglings in brood, meaning that we have a minimum of 15 and maximum of 21 breeding pairs on site. Therefore, even if the minimum is true its still an increase by 2 breeding pairs from last year!
What's more, we have also see that the tree sparrow population has expanded across the site. Last year's unsuccessful colonies over at Powhillon had 37 fledglings this year from 6 boxes. Without this success our population would of actually decreased on site!
It's been amazing to see that the population is still increasing here at WWT Caerlaverock and that the hard work of the reserve team over the last 3 years has paid off.
As a reserve team, we are always hoping to expand the tree sparrow population so we will be looking at where current boxes can be moved and new boxes put up to try to ensure another population increase next year!
Words by Ed (Emily) Dixon
Feature image of a tree sparrow by Alex Hillier