There are 13 species of kestrel in the falcon genus, but only one lives in the Americas - the American Kestrel (Falco sparverius), and is divided into 17 subspecies distributed from Canada and Alaska to Tierra del Fuego in Argentina.
These colorful birds of prey are the smallest falcon in North America and are hugely diverse across their range. For example, some subspecies weigh as much as a Blue jay and others as much as a pigeon or Mourning dove! This is a guide to female American kestrels.
Male and female kestrels are relatively easy to tell apart, as the male is considerably more colorful than his female counterpart. The male has a blue-gray head, wing, and tail plumage, with chestnut-brown feathers on its back, while the female's feathers are mainly brown.
In addition, an adult female sports dark bars across its tail, while an adult male has a brown and gray tail with a black band at its base.
Like other raptors, female American kestrels are larger than males (around 10 to 15%), though the difference isn’t as significant as it is for others (e.g. some female raptors are 25% larger than males).
There is much more to learn about these wonderful raptors - read on to find out!
Close up of a Female American Kestrel perched on a post
The easiest way to tell the difference between male and female American Kestrels is that females are predominately brown, whereas males are chestnut brown and have more slate blue coloring on the wings. Both males and females share the slate blue head.
The male American kestrel is an attractive and colorful falcon with slate-blue wings and head, vertical stripes on the cheeks, chestnut brown feathers on the back, a pale chestnut brown breast and stomach, and a brown tail with black and white stripes at its base.
The most striking difference is that the female lacks most of the slate-blue wings of the male and lacks the contrasting gray and chestnut back feathers. Instead, she’s largely brown, though she still has a slate-blue head.
The female’s chest, breast, and stomach are lighter than the male's. She’s still pretty colorful as raptors go but doesn’t quite match up to the colorful and contrasting male. However, despite his more ornate plumage, the male is smaller than the female, though this is only noticeable if the pair are side by side.
Male American Kestrel
Female American Kestrel
Female American kestrels are predominantly shades of brown, aside from their slate-blue heads and black cheek stripes. Most American kestrels are the size of a jay, measuring 9 inches long (19cm) with a wingspan of around 22 inches (55cm).
Their wings and backs are an attractive chestnut brown with dark brown or black bars. The tail is similar; it’s light brown with darker brown/black sides and dark brown bars across its width.
The female’s chest is a lighter beige-brown with subtle bars. She has two dark face stripes like the male.
Female American Kestrel
Like most raptors, female American kestrels are larger than males. However, in their case, the size difference is around 10 to 15%, which is less than many other raptors, where the female is some 25% larger.
The male typically weighs 80 to 143g (2.8 to 5.0oz), and the female 86 to 165g (3.0 to 5.8oz). As we can see, the difference is quite small and hard to spot unless the birds are right next to each other.
Male (left) and female (right) American Kestrels perched on a wire together
One explanation posited for the size difference between male and female raptors is that this enables them to catch different prey, increasing their diet’s diversity when feeding the chicks.
In studies, the female American kestrel generally takes larger prey than the male. Males were more likely to take birds than females.
Perched Female American Kestrel on the lookout for prey
Males typically establish a territory and advertise it to females by performing dive bombs and fast-flying displays. For example, they repeatedly climb and dive at high speed, emitting a short sequence of klee! calls.
American kestrels take part in what’s known as courtship feeding, where the male feeds the female for up to a month before she lays the eggs and two weeks afterward. Once paired, birds stay together for years or life.
When it’s time to nest, the male inspects nesting sites and leads the female to one. The female excavates the cavity, lays the eggs, and incubates the young. The female usually incubates more than the male, but this does vary.
The male feeds the female when she incubates. Young birds are chiefly fed by the female (the female made 70% of feeding trips in one study).
Female American Kestrel in flight
Males tend to migrate earlier than females and return earlier to their breeding grounds. They’ve also been found to winter further north.
There is little information on sexual differences between American kestrel vocalizations. The female has a high-pitched whining call during the breeding season, but other than that, American kestrel calls are quite limited.
Male American Kestrel in flight - the wing color is one of the easiest ways to tell the difference between the sexes
Female American kestrels perform the majority of the actions and responsibilities required to raise chicks, like excavating the nest, incubating the eggs, and feeding the chicks. It'd still be unlikely for a female to raise her young alone, as she'd potentially struggle to provide enough food.
However, the male does assist in virtually every process, and it’s highly unlikely the female would be able to catch enough prey while simultaneously brooding the chicks. Also, the male plays his part by feeding the female before laying and sometimes throughout the incubation period.
Moreover, these birds are monogamous and form strong, long-lasting pair bonds. Raising chicks is perilous for most raptors which rely on strong partnerships between males and females.
American Kestrel female preparing for take off
American kestrels have a small range of calls, including a klee, whine, and chitter, with some variations thereof. A loud and excitable series of 3 to 6 klee! or kill-e! is one of the most common calls.
The female shares the same core calls as the male but has a specific whining call she seems to use in the breeding season.
Female American kestrels are predominantly brown aside from a slate-blue head similar to the male. Their undersides are lighter brown, whereas their tail and wings are a chestnut brown with darker bars. In addition, they have black stripes on the cheek portion of their heads.
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