American Kestrel

Discover the fascinating world of the American Kestrel, North America's smallest falcon, in this comprehensive guide exploring its size, shape, color pattern, behavior, habitat, interesting facts, and ecosystem services.The American Kestrel (Falco sparverius) is a captivating bird of prey and the smallest falcon species found in North America. With their striking appearance, agile aerial skills, and fascinating behaviors, American Kestrels have captured the admiration of birdwatchers, naturalists, and scientists alike. In this extensive educational blog, we will dive into the world of the American Kestrel, exploring its physical characteristics, habitat, diet, breeding habits, and conservation efforts. Through this comprehensive guide, you will gain a deeper understanding of these remarkable birds and the essential role they play in their ecosystems.

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How to ID a American Kestrel

The American Kestrel is a small, slender falcon measuring 8.7-12.2 inches (22-31 cm) in length, with a wingspan of 20-24 inches (51-61 cm) and a weight of 2.8-5.8 ounces (80-165 grams). They exhibit striking sexual dimorphism, meaning males and females have distinctly different plumage patterns. Males possess slate-blue wings and a rust-colored back, tail, and crown, while females have rust-colored wings and back with dark barring. Both sexes have a white or cream-colored underside with black spots or streaks, as well as bold, dark facial markings that resemble sideburns or "whiskers" [1].

_{(1) Cornell Lab of Ornithology - All About Birds. (n.d.). American Kestrel. Retrieved from https://www.allaboutbirds.org/guide/American_Kestrel}

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1. Size and Shape

The American Kestrel's distinctive long, pointed wings and square-tipped tail provide exceptional maneuverability and control during flight [1]. These adaptations allow the kestrel to hover in place, perform rapid aerial pursuits, and change direction quickly, making it a highly effective hunter. American Kestrels exhibit sexual dimorphism not only in their coloration but also in size, with females being slightly larger than males [1]. This size difference, common among birds of prey, is thought to enable the pair to exploit a wider range of prey sizes and reduce competition for food resources within the family unit.

• Length: 8.7-12.2 inches (22-31 cm)‍
• Weight: 2.8-5.8 ounces (80-165 grams)‍
• Wingspan: 20-24 inches (51-61 cm)

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2. Color Pattern

One of the most striking features of the American Kestrel is its vivid coloration. They exhibit sexual dimorphism, meaning males and females have distinctly different plumage patterns. Males possess slate-blue wings and a rust-colored back, tail, and crown, while females have rust-colored wings and back with dark barring. Both sexes have a white or cream-colored underside with black spots or streaks, as well as bold, dark facial markings that resemble sideburns or "whiskers." This color pattern not only contributes to their beauty but also plays a role in communication and courtship behaviors. The American Kestrel's color pattern not only contributes to its beauty but also plays a role in communication and courtship behaviors. The contrasting colors can be used to signal intentions and emotions to other kestrels, such as during territorial disputes or mating displays [2]. Additionally, the plumage pattern helps to camouflage the kestrel in its environment, providing protection from predators.

Juvenile American Kestrels have a similar color pattern to adults, but with more subdued colors and a greater degree of barring on their wings and tail [1]. As they mature, their plumage will gradually molt and develop into the more vivid adult coloration.

_{(2) Smallwood, J. A., & Bird, D. M. (2002). American Kestrel (Falco sparverius), version 2.0. In The Birds of North America (A. F. Poole & F.B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.602}

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3. Behavior

American Kestrels are known for their fascinating behaviors, including their impressive hunting techniques. They employ various strategies to capture their prey, such as hovering in mid-air to scan the ground below for prey before swooping down to capture it, or perching and waiting patiently for prey to appear before launching a rapid aerial attack [3]. Their agile wings and long tails enable them to perform rapid aerial pursuits and hover in place.

Kestrels are also vocal birds, using a series of high-pitched "klee-klee-klee" or "killy-killy-killy" calls to communicate with their mates, defend their territories, or signal alarm [2]. These calls can be heard throughout the year and are particularly common during the breeding season when pairs are establishing and defending their territories.

During the breeding season, American Kestrels engage in a variety of courtship displays, such as aerial acrobatics, vocalizations, and food exchanges [1]. They are cavity nesters, typically selecting natural cavities in trees, cliff faces, or human-made structures for their nests [2]. Kestrels do not build their own nests but will lay their eggs directly onto the cavity floor or add a minimal layer of materials such as grasses, leaves, or feathers [2].

_{(3) National Audubon Society. (n.d.). American Kestrel. Retrieved from https://www.audubon.org/field-guide/bird/american-kestrel}

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4. Habitat

The American Kestrel is found throughout North, Central, and South America, inhabiting a wide variety of habitats, including grasslands, deserts, open woodlands, agricultural fields, and urban and suburban areas [1]. They prefer open environments with scattered trees or structures that provide perching and nesting opportunities. American Kestrels are highly adaptable birds and can successfully live in urban and suburban environments, where they often nest in buildings or other artificial structures [1]. Their adaptability to a variety of habitats is one of the factors contributing to their widespread distribution and relatively high abundance compared to other raptor species.

In some parts of their range, American Kestrels are year-round residents, while in other areas, they may undergo seasonal migrations [1]. Northern populations typically migrate southward during the winter to escape harsh weather conditions and find more abundant food resources. During migration, kestrels may travel in small groups or individually, using a combination of soaring and powered flight to cover large distances.

Related: Black-capped Chickadees: ID and Overview

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Video on the American Kestrel

"Did you know that kestrels hover in midair before going in on their prey? We invited Rita McMahon and Coral, the non-releasable American Kestrel, from Wild Bird Fund to teach us 5 cool facts about these tiny-but-fierce predators." - https://www.audubon.org/

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Facts about the American Kestrel

1. Smallest Falcon in North America - The American Kestrel is the smallest falcon species in North America and is also known as the "Sparrow Hawk" [3].
2. Ultraviolet Vision - They are capable of seeing ultraviolet light, which helps them detect the urine trails left by small mammals like voles, making it easier for them to locate their prey [4].
3. American Kestrels can reach speeds of up to 40 mph (64 km/h) during level flight and up to 60 mph (97 km/h) when diving towards their prey [3].
4. Their keen eyesight enables them to spot prey from great distances, and they can focus on objects both close and far away simultaneously [4].
5. The male American Kestrel typically provides most of the food for the female and nestlings during the nesting period, while the female protects and broods the young [2].

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Ecosystem Services:

1. As predators, American Kestrels play a vital role in their ecosystems by controlling populations of small mammals and insects [5]. By consuming pest species such as rodents and insects, they help maintain the balance and health of their habitats, benefiting both plant and animal communities.
2. In agricultural landscapes, American Kestrels can be beneficial to farmers by preying on pest species like insects and small mammals that can damage crops [5]. They also contribute to natural pest control in urban and suburban environments, helping to keep rodent populations in check.
3. Conserving the American Kestrel and its habitats supports overall ecosystem health and biodiversity, ensuring that these captivating birds continue to thrive and contribute to the balance of nature [5].

The American Kestrel is a remarkable bird with a striking appearance, fascinating behaviors, and essential role in its ecosystems. By gaining a deeper understanding of their size and shape, color pattern, behavior, habitat, interesting facts, and ecosystem services, we can appreciate the unique adaptations and contributions of these small falcons. Let us work together to protect and conserve the American Kestrel and its habitats for future generations to enjoy.

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