Northern Harriers often choose to breed in large stretches of undisturbed grasslands and wetlands across the state. They will use meadows, old farm fields, pastures, and both freshwater and brackish marshes during the breeding season where they can be seen hunting for small rodents and birds.
Where to look for Northern Harrier in the final year of the Atlas
Below is a map highlighting atlas priority blocks missing Probable or Confirmed codes for Northern Harrier, but where the NY Natural Heritage Program has records of Northern Harrier breeding in the past. Keep an eye out in these blocks for Northern Harrier breeding behaviors! (Tip: Click on the icon in the upper right of the map to make the map full size and zoom in to your area.)
Behaviors to look for
In the early breeding season, keep an eye out for males performing Courtship flights (C) over and around a watching female. These flights are often described as being rollercoaster-like as the males will gracefully fly in an up-and-down pattern, potentially reaching 1,000 feet up and flying over the course of a half mile. During a courtship display, listen for the male and female as they often make a quick series of kek, or cluck, calls.
Keep an eye out for females and males Carrying Nesting Material (CN) as they fly across the open grasslands or wetlands in your area. Northern Harriers typically nest on the ground in a dense patch of vegetation. Male harriers will help bring material to the nesting site, but the female will do most of the building by using thicker plant materials for the base and having a finer lining of sedges and grasses. They can take 1-2 weeks to build their nests, giving a solid window to catch them carrying nesting materials.
Male and Female Northern Harriers are known to be aggressive in protecting their territory and nest site. Females will often chase away other females, and males will chase off other males, so watch for Territorial Behavior (T) throughout the breeding season. It takes roughly 30 days for the female to incubate her eggs, and another 15 for the young to fledge from the nest, and the adults will show Agitated Behavior (A) when potential predators approach their nest site by circling and diving on predators and making their kek, or cluck, calls. Since the female does all of the incubation and brooding of the young, the male will bring her food. If a female gets particularly hungry and tired of waiting for food while incubating and brooding, they will give a higher pitched shriek to remind the male that she needs more food.
While it is difficult to spot a nest, or a female sitting on a nest, pay close attention later in the season to where the adults are carrying food items. Although raptors do not always carry food for young, you may catch where they are Feeding Young (FY) before or after they fledge.