Understanding Breeding Codes

By Lee Sherrill and John Carpenter 27 Jun 2023
©John Troth I Female Eastern Towhee Carrying Nesting Material (CN)

A common question we often receive is, “What makes Atlasing different than eBirding?”  The correct response has more than just one answer!  Guidelines like focusing on priority blocks, traveling <1 mile, and Atlasing for <1 hour on each checklist are just a few examples.  However, one of the biggest (and most important) differences between Atlasing and eBirding is the use of breeding codes. This extra step will allow us to understand to what degree (Possible, Probable, or Confirmed) a species attempted to breed in North Carolina. Some codes will even provide us with enough information to determine that the species not only attempted but was successful.

Most breeding codes represent a particular behavior, for example singing (S) or carrying food (CF).  That is why you will sometimes see them referred to as Breeding and Behavior Codes on eBird’s website (but only as Breeding Codes when entering Atlas data). For those Atlasers who have been with us since the beginning, you may recall being encouraged to simply document the behavior regardless of the date, location, or the species’ ecology, and to let the data reviewers interpret the breeding status for that checklist. The initial intent of inclusivity for all skill levels, and maximized data flexibility led to unintended consequences.  In practice, this approach increased confusion – why use a breeding code for a species that is only migrating through North Carolina?

As a result, we updated the breeding code usage guidelines as follows:

  1. When deciding on a code, remember that they are for determining breeding status.
  2. Know the code definitions. (See detailed definitions at: breeding-behaviors.ncbirdatlas.org).
  3. Record appropriate codes whenever observed (see #2).
  4. If you are unsure about a code, use your best judgement for the most appropriate one, and leave a comment with the species.

Using breeding codes generally requires an Atlaser to slow down a bit and take the time to truly observe a bird’s behavior.  Including breeding codes in a checklist, when applicable, is easier than you might think.

     

Image on left: After clicking on the species name in your checklist, this screenshot shows the eBird phone app allowing the option to “Add breeding code”

Image on right: Screenshot of eBird phone app showing breeding code options after “Add breeding code” was selected.

Simply click on the species name of the bird you observed, and then click on “add breeding code.” Next, you’ll be asked to choose a breeding code from the list of 22 codes.  These codes are arranged into one of three categories: “possible,” “probable,” and “confirmed” (“F” for flyover is not a breeding code and is the only code that falls within the “observed” category).  Each individual code is colored-coded to show the user which of the three categories the code falls within.  For example, “S” for singing falls within the possible category and is the lightest shade of purple. As we move from the possible to confirmed codes, our level of confidence that a particular species is breeding in that habitat and during that particular time of year increases. Simultaneously, the richness of the shades of purple increase.  A nice feature within the eBird app is the “information” or “i” icon next to breeding codes that helps to explain when to use each breeding code.  Alternatively, one can visit breeding-behaviors.ncbirdatlas.org to study ahead of time before heading out into the field.

Breeding codes serve as the foundation for many management decisions; they help scientists and wildlife agencies better understand the phenology (timing of biological events) of different bird species that breed in N.C. and can help influence conservation efforts across the southeastern U.S.

Profound thanks to every atlaser who takes the time to observe and enter breeding codes in your NCBA portal lists so that together we can responsibly and responsively direct wildlife management of birds in N.C.

*For a deeper dive into breeding codes and data quality, click here.