[CT Birds] Some Comments on Connecticut Bird Atlas Safe Dates, Part IV

Stephen Broker stephenpaulbroker at gmail.com
Sun Apr 8 07:11:48 EDT 2018

Three statements from the Connecticut Bird Atlas website are important to keep in mind when submitting evidence of breeding behavior.  Here they are, taken from the website. 

(1) “Breeding codes, especially those in the Possible and Probable categories, generally should not be used outside the safe dates for a given species.  Confirmed breeding codes are less likely to cause errors, but even confirmed breeding should be well documented (e.g., a detailed description of the bird species and the behaviors that confirm breeding) if it happens outside the safe dates for a species because these records are likely to be of particular interest.” (from Surveys - Safe Dates and Habitats)

(2) A word of warning:  Many of the coded breeding behaviors that appear under the possible and probable categories may also be seen in birds during migration (e.g., singing male warblers or a pair of ducks.). If you find a species exhibiting apparent breeding behavior in a place where it is unlikely to nest, either because the habitat is unsuitable or because you are outside its normal breeding range, and you are still within the migration period of that species, then recording the bird as simply Observed (code X, see below . . .) is probably appropriate. (from Documenting breeding evidence)

(3) Safe dates:  These are dates between which breeding is known to occur. . . Our safe date list is based on one being used by the Rhode Island Bird Atlas and has been found to be accurate for most species over the past two summers. If, however, you detect strong breeding evidence outside a species’ safe dates, the record is likely to be particularly important, and we want to document the case carefully.  (from Documenting breeding evidence)

There is a potentially tricky balance between, on the one hand, making observations that suggest a given bird species is in the breeding period and, on the other, not being misled by behaviors exhibited by migrants or by resident birds that may not in fact lead to breeding.  In other words, we need to use breeding codes that are applied properly to behaviors observed in the field (Get the Evidence), and we need to be mindful of safe dates (Curb Your Enthusiasm).

My next and last post on safe dates will address solid evidence of confirmed breeding outside safe dates by three species of early breeding birds.

Steve Broker


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