A productive season

This season has been relatively productive but has not broken the record of 2013. However, we did record 4 successful clutches from 2 pairs, which is pretty uncommon for bluebirds who are known to make up to 3 nesting attempts when successful. These ambitious pairs with high fidelity to their mate were therefore the last to finish fledging young, making this season break the record of latest fledging event.

Here is a little comparative summary:

- First egg date:

2016: 18 March

2015: 28 March

2014: 27 March

2013: 23 March

2012: 15 March

- Last fledge date (picture shows a chick ready to fledge from the first clutch of one of the 2 ambitious pairs this year):

2016: 18 September

2015: 2 September

2014: 13 September

2013: 21 August

- Number of clutches that survived to day 13 after hatching:

2016: 131

2015: 107

2014: 109

2013: 140

- Number of chicks banded:

2016: 531

2015: 424

2014: 446

2013: 566

- Number of new adults:

2016: 53

2015: 44

2014: 52

- Number of recaptured adults:

2016: 122

2015: 111

2014: 105

2013: 123

- Missing: Some clutches that seem healthy at day 7 have missing chicks at day 13. Predation seems unlikely because snakes don't eat 1-2 chicks to leave the others alive; raccoons and cats disturb the nest... Maybe the chicks died in the nest and the parents are strong enough to carry them out and away from the box. What is the maximum size/age they can carry away? I wonder.

- Delayed incubation: It is not uncommon at the beginning of the nesting season, when it's still cold at night, for females to delay incubation of their newly laid eggs. But this is the first time that I observe a 4-day delay in the middle of June, when temperatures are high and fairly constant. Even stranger is that the female had previously raised clutches (this season and last year) on a normal schedule.