Closing out monitoring for the past few weeks, I’ve found no casualties at the Noble Research Center during surveys 26–30 November, and on the following dates in December: 3, 4, 5, 6, 10, 11, 12, 13, 14, 18, and 20. November 16th produced the last casualty, an Orange-crowned Warbler, on the heels of our cold snap and snowfall beginning 12 November.
I slow the pace of surveys a bit during winter, but plan to continue monitoring through January and February 2019 to capture “winter”, but the great majority of fall/winter collisions occur in September and October here. March 2019 will mark the beginning of my currently planned final season of collision mortality monitoring at the NRC, to include spring and summer of the coming year. By the end of July 2019, I will have completed 10 years of near daily monitoring for casualties at this one building.
I haven’t analyzed this, but there have been many occasions that some unusual casualty will show up and another will appear on its heels – or on the same day. These events make me wonder about pairs migrating together or, at the very least, individuals from the same regions departing at about the same time and following similar routes. How else would we explain the 9th and 10th Orange-crowned Warblers hitting the same building less than 24 hours apart?