The most commonly encountered species in Maine, American Crows breed state-wide and can be seen in large roosts during the winter. Their adaptability makes them a successful species in a variety of habitats. During the time between these two atlases, crow populations dropped due to high mortality from mosquito-borne West Nile Virus. Maine’s population appears to have recovered since that time but time will tell how they are fairing on smaller regional scales.
Breeding Codes
In each category below, we give examples of some of the breeding codes to look for with this species. Please refer to page 18 of the Volunteer Handbook for complete descriptions of each code.
Safe Dates: 15 April – 15 July
Possible
American Crows use their “song” apparently as an intragroup bonding mechanism so singing (S) should not be used with this species. Their nesting habitat is incredibly variable – primarily in conifer, but also uses deciduous forests and mixed. They can be found nesting everywhere from urban parks to rocky islands so a bird in appropriate habitat (H) is a fairly common code with this species. As always, you should spend time watching the bird to see if there is some indication that bird is actually likely to use that habitat.
Probable
Since S is ruled out (above), M and S7 should also not be used for this species. Looking for a pair in suitable habitat (P) is a good code for bumping up from H (possible) but use caution with this code as sexes cannot be identified in the field. Also, be careful not to count offspring following adults as pairs. Crows tend to be very territorial (T), especially towards any birds (raptors in particular) larger than themselves. Use habitat indicators, like the birds flying from pines (a probable nest site) to indicate the bird is actually nesting locally rather than just harassing a passing bird.
Allopreening is often observed between mates and can be coded as courtship (C). They also have some precopulatory displays which are very similar to begging juveniles, so use cation to not accidentally code the display as a recently fledged young (time of year should help here).
Confirmed
The most commonly reported confirmed behavior for American Crows is observing recently fledged (FL). Young crows are completely dependent on their adults for food for 2-3 weeks after fledging but can remain with the adults for two months or longer. Because of this long period of adult care after fledging, you may be observing some of these behaviors far from the sites where the birds nested. Think about the development of the young (how old they are) and the habitat types (were they likely to nest within that block) before using the FL code. Adults are fairly easy to detect carrying nesting material (CN) since they will use larger sticks in their nests, though the actually nest building (NB) can be hard to see. Adults will delivery a wide variety of food to their young (CF) but be careful to make sure these are actually food deliveries, not just the adults carrying food to a safe place for their own consumption. As an example, crows are often seen scavenging carrion from the roadside and will typically fly off with bits for their own consumption at a safe place, free of oncoming traffic.
American Crow carrying nesting material.