Birds of the California Delta (Page in Progress)

The Red-tailed Hawk (Buteo jamaicensis) is the most widespread and familiar large hawk in North America, known for its iconic brick-red tail and broad, rounded wings. Often seen perched on roadside poles or soaring in wide circles over open fields, it is a versatile predator that has adapted well to both wild and urban environments. 

Key Characteristics

• Appearance: Adults are typically brown above and pale below with a dark "belly band" of streaks. Their most famous feature is the cinnamon-red tail, though immature hawks have brown tails with dark bars.
• Size: They are large raptors with a wingspan of roughly 4 feet (110–145 cm). Females are generally 25% larger than males.
• Vocalization: Their call is a raspy, descending scream (kree-eee-ar). This sound is so "iconic" that Hollywood often uses it as a sound effect for bald eagles and other birds of prey.
• Hunting & Diet: Primarily "perch hunters," they scan for movement from high vantage points before diving. Their diet consists of 80–85% small mammals like rodents and rabbits, though they also eat reptiles, birds, and carrion. 

Behavior and Life Cycle

• Mating: They are monogamous and often mate for life. Courtship involves spectacular aerial displays where pairs may lock talons and spiral toward the ground.
• Nesting: Pairs build bulky stick nests in the crowns of tall trees, on cliff ledges, or even on urban structures like billboard platforms.
• Lifespan: While many die within their first two years, those that survive can live for more than 20 years in the wild; the oldest recorded wild individual was over 30 years old. 

Habitat and Range: Red-tailed hawks are found across North America, from central Alaska and Canada south to Panama and the West Indies. They prefer open country interspersed with patches of trees for nesting and perching. While some populations are permanent residents, those in the northernmost ranges migrate south for the winter. 

Conservation and Cultural Significance

• Legal Status: They are protected under the Migratory Bird Treaty Act, making it illegal to kill, harass, or possess them (or their feathers) without federal permits.
• Falconry: Due to their abundance and trainability, they are the most common hawk used by falconers in the United States.
• Native American Culture: Many indigenous tribes consider the red-tailed hawk and its feathers sacred, viewing the bird as a spiritual messenger or a symbol of strength. 

The Northern Harrier (Circus hudsonius), also known as the Marsh Hawk, is a unique medium-sized bird of prey found throughout North America. It is distinguished by its owl-like face and its habit of gliding low over marshes and grasslands with its wings held in a characteristic dihedral (V-shape). 

Key Identification Features

• White Rump Patch: A distinctive bright white patch at the base of the tail, visible in all plumages and most obvious during flight.
• Sexual Dimorphism: This species shows striking differences between sexes:
  • Males ("Gray Ghosts"): Pale slate-gray above and white below with black wingtips.
  • Females & Juveniles: Predominantly dark brown above with buff, streaked underparts.
• Facial Disk: Like an owl, it has a ruff of stiff feathers that funnels sound to its ears, allowing it to hunt by sound as well as sight. 

Habitat and Behavior

• Habitat: It prefers wide-open spaces such as marshes, prairies, meadows, and agricultural fields.
• Hunting: It "quarters" low over the ground (often just 10–30 feet up), listening for the rustle of small mammals like voles and mice.
• Nesting: Unlike most hawks, it nests on the ground in dense vegetation or marshes.
• Courtship: Males perform a spectacular "sky dance," an aerial display involving steep dives, loops, and barrel rolls to attract mates.
• Social Structure: They are one of the few raptors known to practice polygyny, where one male may mate with up to five females in a single season. 

Conservation Status

• While still common in many areas, populations are declining due to habitat loss from wetland drainage and agricultural expansion. It is state-listed as endangered or threatened in several northeastern states, including Massachusetts, New York, and Pennsylvania.
  
  

White-tailed kite (Elanus leucurus) is a medium-sized raptor known for its striking white plumage, black shoulders, and unique "kiting" hunting behavior. 

Identification & Description

• Appearance: Adults have a white head and underparts, light gray back, and prominent black "shoulders" (wing coverts). Their eyes are a piercing deep red.
• Size: They typically measure 12.5–15 inches in length with a wingspan of about 40 inches.
• Juveniles: Distinguished by a "scaly" brown appearance on their back and a cinnamon-colored wash across their chest. 

Behavior & Diet

• "Kiting": Their most famous trait is the ability to hover in one spot while facing into the wind, rapidly beating their wings as they scan the ground for prey.
• Diet: They are small-mammal specialists; over 95% of their diet consists of rodents like voles and field mice.
• Roosting: During the non-breeding season, they are highly social and can form communal roosts of over 100 birds. 

Habitat & Range

• Environment: They inhabit open grasslands, savannas, marshes, and agricultural areas where prey is abundant.
• Distribution: Their range includes the Pacific Coast (Washington to California), southern Texas, and Florida, extending through Mexico and Central America to South America.
• Conservation: Once near extinction in the early 20th century due to hunting and egg collection, their populations have since rebounded, though they remain a "fully protected" species in states like California. 

Reproduction

• Nesting: Pairs are typically monogamous. Nests are built of twigs near the tops of trees, often 20–50 feet high.
• Breeding Season: Generally February to October. The female typically lays 3–6 cream-colored eggs with brown splotches.
• Courtship: Includes spectacular "flutter flights" and aerial prey exchanges where the male passes food to the female in mid-air. 

The Red-shouldered Hawk (Buteo lineatus) is a medium-sized raptor native to North America, recognized for its vibrant coloration and distinctive, piercing calls.

Key Characteristics

• Appearance: Adults feature a rich reddish-brown barred chest and belly, dark brown upperparts, and namesake rufous "shoulder" patches. Their tails are black with several narrow white bands.
• Flight Identification: In flight, they display translucent, crescent-shaped "windows" near their wingtips.
• Vocalization: Known as one of the most vocal hawks, they emit a loud, repeated "kee-aah" or "kee-yer" scream, which is often mimicked by Blue Jays.
• Size: Typically 16–24 inches long with a wingspan of roughly 37–44 inches. 

Habitat and Range: Red-shouldered hawks prefer mature deciduous forests and bottomland hardwoods, particularly those near water sources like rivers, swamps, and wetlands. They have two distinct populations: 

• Eastern Population: Ranges from southeastern Canada through the eastern United States to central Mexico.
• Western Population: Found along the Pacific Coast from Oregon through California. 

Diet and Behavior

• Diet: They are generalist hunters, consuming small mammals (voles, chipmunks), amphibians (frogs, toads), reptiles (snakes, lizards), and occasionally crayfish or small birds.
• Hunting: Chiefly "perch-hunters," they sit silently on branches or utility wires before dropping swiftly to strike prey on the ground.
• Breeding: They are monogamous and often return to the same nesting site year after year. Courtship involves spectacular "sky-dancing" aerial displays by the male.

Conservation: While currently considered a species of "Low Conservation Concern" globally, they face threats from habitat loss and fragmentation, which often leads to them being outcompeted by the more open-country Red-tailed Hawk. Like all North American raptors, they are protected under the Migratory Bird Treaty Act.