There are a few different birds that are known for making high-pitched whistling or chirping sounds at night. Here are some of the most likely culprits:
Northern Mockingbird
The Northern Mockingbird is one of the most likely birds to be making a loud, high-pitched whistle at night. Mockingbirds are known for their ability to mimic other birds’ calls and songs, and they are most active at night when defending their territory.
Mockingbirds have a complex repertoire of sounds that include chirps, gurgles, squeaks, and their famous whistles. Their nighttime whistles are often very high-pitched and can sound similar to a flute or pennywhistle. The whistles are louder and more frequent during the spring and early summer when males are establishing territory and attracting mates.
European Starling
The European Starling is another bird that makes high-pitched chirping noises at night. Starlings produce a wide variety of vocalizations including clicks, whistles, and screeches. Their nighttime chatter is thought to help starlings communicate with each other and establish social hierarchies as they gather in large flocks to roost for the night.
You may hear starlings making loud, high-pitched squeaking or whistling calls consisting of a jumbled series of notes and tones. The calls often speed up and get louder when the birds are alarmed or excited.
Mourning Dove
Mourning Doves are known for their mournful cooing sounds, but they can also make a high-pitched whistling call, especially at night. The whistles are thought to be contact calls that help doves communicate with other doves and find each other at dawn and dusk when they are most active.
Dove whistles are simple, plaintive notes often repeated multiple times in a row. They have a piercing, far-carrying quality that can easily be heard at night when ambient noise levels are lower.
Killdeer
Killdeer are shorebirds that inhabit open fields, lawns, and golf courses as well as natural wetlands. They are active both day and night. At night, killdeer will make a loud, piercing “kil-DEE” call that has a whistling quality to it.
The killdeer’s nighttime whistling is thought to help the birds stay in contact with each other and defend territory. The calls can sound anxious and insistent when the birds are alarmed. Killdeer breed during the spring and summer, so their calls are most noticeable during the breeding season.
Common Nighthawk
Common Nighthawks are members of the nightjar family that includes birds like whip-poor-wills. They make a loud, harsh whistling sound as part of their territorial displays during breeding season.
The nighthawk’s whistle is actually created by wind rushing through specialized wing feathers during a sharp downward dive. The whistles have a mechanical, booming quality and may be repeated over and over as the birds swoop around at night.
Eastern Screech Owl
While not technically a whistle, the Eastern Screech Owl does make a very high-pitched, shrill whinny during the nighttime hours. This mostly nocturnal species uses the whinny to communicate with other screech owls when defending territory and attracting mates.
The screech owl’s whinny goes up and down in pitch and lasts for several seconds. The owls also produce a series of short, wavering hoots but the whinny is higher-pitched and more penetrating to human ears.
Flammulated Owl
The Flammulated Owl is a small owl species that migrates through certain parts of the western U.S. during the summer breeding season. At night, the owl produces a repetitive, whistle-like hooting call described as ow ow ow-ow ow ow.
Each call starts with low hooting notes that become higher-pitched and trail off with a distinctive whistle at the end. Flammulated owls are usually most active in calling around dusk when establishing nighttime territories.
Acadian Flycatcher
The Acadian Flycatcher is a small songbird that makes a rising, whistle-sounding call described as peet-seet. The call is two syllables with the second being higher pitched and more whistle-like than the first.
Acadian flycatchers deliver these calls as contact calls between mates and during territorial displays, often at dawn and dusk. The whistling quality helps the call carry farther so birds can stay in touch when obscured by foliage.
Conclusion
In summary, some of the most likely bird suspects for nighttime whistling include mockingbirds, European starlings, mourning doves, killdeer, nighthawks, screech owls, flammulated owls, and Acadian flycatchers. The whistling sounds help these birds communicate over distances, attract mates, and defend territories during the breeding season when activity increases at dawn and dusk.
Identifying whistling birds at night takes some experience matching the unique tone and pitch of each species’ vocalizations. With practice, birders can quickly learn to recognize the nighttime whistlers in their area based on subtle differences in the whistling quality and pattern.