Species spotlight - Tree sparrow

The tree sparrow (Passer montanus) is in the family of old world sparrows.

This passerine is easily identifiable due to the brown chestnut cap on the top of the head. Between the sexes there is no difference which is quite unique in birds as the majority show profound sexual dimorphism. At Caerlaverock they are somewhat of a common species whereas this cannot be said for the rest of the UK. They are a red listed species with a declining population trend due to an intensification of farming and increased use of pesticides and herbicides across Europe and the UK.

However here at WWT Caerleverock we have a stronghold population of tree sparrow due to great work carried out by the team. Success has been seen in Dumfries and Galloway for attracting and retaining tree sparrow colonies due to the impressive number of nest boxes that have been constructed throughout the years. These boxes have led to an influx of juvenile’s birds that have been successfully fledged on site that has bolstered the population. On site we have over 50 boxes with various clusters of boxes dotted around the site in hope that additional colonies will form to create an even stronger population for this amazing little passerine.

Over the coming months the monitoring process will start. The focus will be on tree sparrows and their potential fledging chicks but we will also be monitoring our little owl, barn owl and kestrel boxes that have been constructed this winter. Surveying will include observing each nest box for a period of time and recording any behaviour that may occur if any nesting behaviour is observed physical checks will be undertaken. This will be carried out be examining each next box and recording data based on what is observed in the box. Head to WWT Caerlaverock to check out our amazing colonies of tree sparrows!

Written by Jacob Campbell
Feature photo by Fiona Moir

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