Date: 9/8/26 12:53 pm From: Stephen Broker via CTBirds <ctbirds...> Subject: [CT Birds] Some Comments on Breeding Codes and Safe Dates - Part I Breeding Codes
One of the many enjoyable aspects of seeing birds in their natural environments is the observation of breeding evidence during the breeding season. This was especially true for me during my field work for the Connecticut Bird Atlas (2018-2021). My interest in breeding birds continues to the present, especially with those species that I have been studying on a long-term basis: peregrines, ravens, and marsh birds.
The website for the Connecticut Bird Atlas (https://draft.ctbirdatlas.research.uconn.edu/) lists the methodology followed for Atlas field work. Two essential documents with which to be familiar are the Breeding Field Card, which list Breeding Codes for determining breeding evidence, and Safe Dates for each bird species found or suspected of breeding in Connecticut. These lists were expected to be used by anyone submitting breeding evidence to the Atlas or in eBird posts.
Possible breeding in the state includes birds seen or heard singing in suitable habitat, and it applies only to birds observed during their published safe dates. There are multiple ways to collect evidence for Probable breeding or Confirmed breeding in Connecticut. Probable breeding includes multiple (7+) singing males in suitable habitat, a pair in suitable habitat during the breeding season, courtship behavior, a bird visiting a probable nest site, and a bird carrying nest material (except for wrens).
There are a dozen ways for Confirmed breeding, the strongest evidence one can obtain in the field. Examples of Confirmed breeding include nest building (except for wrens and woodpeckers), an occupied nest, nest with eggs, nest with young, recently fledged young, and adult feeding young. As noted above, the complete list of Breeding Codes is available on the Atlas website, which continues to be built up in excellent fashion. Birders familiar with and continuing to use these breeding codes are to be commended. But, that’s only half the process. See Part II Safe Dates.
Steve Broker
Cheshire
To subscribe or unsubscribe via email, send an email with just "join" or "leave" in the subject or body to: <ctbirds-request...>
CTBirds, a service of Connecticut Ornithological Association - Bringing birders together statewide. Please support COA: https://www.ctbirding.org/join-us/
