This is a brief end-of-year report for 2023.
Before the season began, we put up the two new House Sparrow resistant boxes and the one good box that was taken off an old “No Parking” sign last Fall. The good news is that we did not have any House Sparrow nests this year. However, the new boxes were nott used by Eastern Bluebirds either. We will need to observe longer to evaluate how well the boxes will work. There is a base with a hole on one side that can be removed or flipped – we can experiment to see whether any of these options seem to affect the bluebird use of the boxes.
This year the number of successful broods was like last year. There was only 1 known successful Bluebird brood nesting in our 13 boxes, yielding ~4 fledglings. There was 1 successful Black-capped Chickadee brood. Because the House Wrens now tend to fill the box with sticks when making their nests, it is difficult to open the boxes and we risk damaging eggs or letting wren babies fledge prematurely if we try to check inside the nest. So, we have decided to only monitor those boxes from the outside. We had 6 boxes filled with House Wren nests. In years past, we have seen House Wren nests yield 1-2 broods. Five of the 6 House Wren nests were completed early enough to yield 2 broods over the summer, and we observed other signs of House Wren activity around these 6 boxes, so we assume there were 6-11 House Wren broods this year, indicating that House Wren numbers may be picking up. High House Wren numbers seem to correlate with low Bluebird numbers since the birds often destroy each other’s nests, eggs, and even young. Most of the evidence this year indicates House Wrens being aggressive to both Black-capped Chickadees and Eastern Bluebirds. The only other possible (chickadee) brood loss was in box 13 which was near the road work done along Elmwood Avenue – when they removed the road section and replaced it with grass.
Let us know if you have any suggestions or comments.
Sheryl Gracewski