Task 4 – Breeding Bird Atlasing

A part of birding during breeding season is determining what birds are breeding in an area. We do this by designating the probability that a particular species is breeding by the observation of clues. The 3 levels of probability are:

CONFIRMED – The species is definitely breeding in this area. There is evidence which shows conclusively that breeding of that species has or is occurring locally.

PROBABLE – The species is probably breeding locally based on observed evidence, but the evidence is not conclusive.

POSSIBLE – The species might be breeding locally, but there is limited or no evidence of it. The bird could be just passing through on its migration or might be present but not breeding.

The codes below are the ones that you can enter while eBirding. The goal is to use the highest level of evidence possible, and the list is arranged from highest level of confirmed down to a flyover, which would in all likelihood not be breeding.

Singing Grasshopper Sparrow

Singing Grasshopper Sparrow


NY Confirmed–Nest with Young — Nest with young seen or heard.

NE Confirmed–Nest with Eggs — Nest with eggs.

ON Confirmed–Occupied Nest — Occupied nest presumed by parent entering and remaining, exchanging incubation duties, etc.

FL Confirmed–Recently Fledged young — Recently fledged or downy young observed while still dependent upon adults. Y ou’ll often see the large mouth or the young begging for food. Juvenile birds which could clearly fly some distance would not count toward this code.

FY Confirmed–Feeding Young — Adult feeding young that have left the nest, but are not yet flying and independent (should not be used with raptors, terns, and other species that may move many miles from the nest site).

CS Confirmed–Carrying Fecal Sac — Adult carrying fecal sac. Adult birds will carry this waste away from the nest.

CF Confirmed–Carrying Food — Adult carrying food for young (should not be used for corvids, raptors, terns, and certain other species that regularly carry food for courtship or other purposes).

DD Confirmed–Distraction Display — Distraction display, including feigning injury. The killdeer’s broken wing display is the obvious example here.

NB Confirmed/Probable–Nest Building — Nest building at apparent nest site (should not be used for certain wrens, and other species that build dummy nests).

CN Confirmed/Probable–Carrying Nesting Material — Adult carrying nesting material; nest site not seen.

T Probable–Territory held for 7+ days — Territorial behavior or singing male present at the same location 7+ days apart. This requires a return visit to the same location at least a week later.

C Probable–Courtship, Display or Copulation — Courtship or copulation observed, including displays and courtship feeding.

N Probable–Visiting probable Nest site — Visiting repeatedly probable nest site (primarily hole nesters).

A Probable–Agitated behavior — Agitated behavior or anxiety calls from an adult (ex. “pishing” and strong tape responses).

PE Probable–Brood Patch and Physiological Evidence — Physiological evidence of nesting, usually a brood patch. This will be used only very rarely.

P Possible–Pair in suitable habitat — Pair observed in suitable breeding habitat within breeding season.

S Possible–Singing male — Singing male present in suitable nesting habitat during its breeding season.

H Possible–In appropriate habitat — Adult in suitable nesting habitat during its breeding season.

F Flyover — Flying over only. This is not necessarily a breeding code, but can be a useful behavioral distinction.