Final statistics of Swallow Nest Boxes at Buttertubs West Marsh.
Number of boxes: 30
Number of boxes with eggs: 25 (83%)
Number of eggs laid: 154
Mean clutch size (range): 5.5 (2-7)
Number of eggs hatched (% eggs hatched): 104 (68%)
Number of nestlings banded (% nestlings banded): 82 (79%)
Number of females banded: 30
Number of males banded: 1
Number fledged (% nestlings fledged): 62 (60%)
% eggs to fledglings: 40%
Fledging rate (young per pair): 2.2
Summary statistics of Tree Swallow nesting productivity at Buttertubs West Marsh during 2020-2024, and 10-year average.
| Parameter | 2020 | 2021 | 2022 | 2023 | 2024 | 12-year Average |
| Number of boxes | 36 | 36 | 36 | 36 | 30 | — |
| Number of boxes with eggs (% of boxes with eggs) | 31 (86%) | 27 (75%) | 20 (56%) | 24 (67%) | 25 (83%) | 21 (67%) |
| Number of eggs laid | 203 | 194 | 131 | 138 | 154 | 128 |
| Mean clutch size (range) | 5.0 (1-7) | 5.1 (3-7) | 5.7 (2-7) | 5.3 (3-6) | 5.5 (2-7) | 5.1 |
| Number of eggs hatched (% eggs hatched) | 158 (78%) | 119 (61%) | 116 (89%) | 120 (87%) | 104 (68%) | 95 (73%) |
| Number of nestlings banded (% nestlings banded) | 101 (64%) | 88 (74%) | 115 (99%) | 97 (81%) | 82 (79%) | 79 (84%) |
| Number fledged (% nestlings fledged) | 85 (54%) | 50 (42%) | 102 (88%) | 83 (69%) | 62 (60%) | 60 (66%) |
| % eggs to fledglings | 42% | 26% | 78% | 60% | 40% | 48% |
| Fledging rate (young per pair) | 2.1 | 1.3 | 4.4 | 3.2 | 2.2 | 2.5 |
