Nocturnal Atlasing Guide

By Julie Hart March 30, 2021
Great Horned Owl Bubo virginianus

Nocturnal birding holds many exciting birding adventures. Whether it’s the skydance of an American Woodcock overhead, or a realization of how many owls or rails live in the forests and marshes near you, there’s so much to learn. This article is here to help demystify atlasing at night, and give you the keys to a whole new fun way to bird.

Jump to focal species for Mar-Apr
Jump to focal species for May-Jul


Planning your nocturnal atlasing

The best way to start any atlasing, at any time of day or year, is with a plan! The core of any atlasing plan is where you want to go, and what you want to find.

At this point, essentially every priority block could use more nocturnal atlasing. This is why this type of atlasing is so important: to ‘complete’ a block for the Atlas, the goal is for two hours of nocturnal birding, ideally on two visits, one each during the early March-April period, and then once later in May-July. A nocturnal checklist in eBird is a list that starts later than 20 minutes after sunset, or earlier than 40 minutes before sunrise. Make sure to keep separate checklists for daytime and nocturnal birding.

Map of nocturnal effort as of March 30, 2021.

To find places near you where your nocturnal atlasing can be most valuable, go to the Effort Map, and choose “Nocturnal Effort Hours” from the dropdown in the upper left. Any blank priority block would be the top priority, followed by any with less than two hours of effort.

Now that you’ve found some blocks where you want to go, it’s time to define the specific places you want to visit in the block(s), and what you want to find. Check out the species- and season-specific tips below on where and when to find the birds you are targeting, and use that to finalize your plan.


Searching for nocturnal species in the field

Nocturnal birding has one obvious difference from daytime birding: you can’t really use your eyes! Nocturnal atlasing is almost invariably sound-based, and learning where to listen, and what to listen for, is key. For better listening, atlas on nights with lower wind.

Nocturnal atlasing has two general seasons, March-April, and May-July. In each season there is a set of species that are at peak breeding activity, and even though some species are present throughout both seasons, it’s recommended to focus on each bird during the species’ peak season. And if you don’t detect any species at all on your nocturnal lists, that’s great data too! Just submit your no-species checklist like any other eBird checklist.

Below we have species-by-species tips for each season for key nocturnal species, focusing on optimal habitats, the optimal time of night to search, and what sound(s) and behavior(s) to keep an ear out for. There may be other habitats that aren’t described, and all below species can sing or call at any time of night, but the below descriptions are the most effective and efficient approaches.


March-April Focal Species

 

American Woodcock 

  • Map of atlas records
  • Habitat:
    • Fields & clearings adjacent to young forest, ideally with some scattered cover
  • Time of night
  • Key tips, sounds, and behaviors
    • To be most efficient at finding woodcock, check out a satellite map of the priority block(s) you’re interested in covering, and pick out fields next to forest that look like they’re not short-cropped lawns. Powerline cuts can be great spots to target. Listen for the peent call (coded S) and the twittering of the bird in flight (coded C). The peent is given from the ground, and the twittering from the air. See the species spotlight for more tips.


Wilson’s Snipe 

  • Map of atlas records
  • Habitat
    • Wet grassy fields, sedge marshes, bogs
  • Time of night
    • Dawn and dusk
  • Key tips, sounds, and behaviors
    • The habits of this species are similar to American Woodcock. The “tuk-tuk” call (coded S), given from the ground or low perches like fence posts or wires, acts as the song and can be heard much farther than the “peenting” of the woodcock. The winnowing display flight (coded C) will be heard overhead, and starts earlier in the evening and ends later in the morning than woodcock display flights.

Eastern Screech-Owl 

  • Map of atlas records
  • Habitat
    • Woodlands, especially near water and at lower elevations
  • Time of night
    • Most vocal close to sunset, quieting further into the night
  • Key tips, sounds, and behaviors
    • Calls more frequently around full moons and before storms. More vocal early in nesting (e.g., April) and again when young fledge (July-August). Listen for the characteristic “whinny” and trilling tremolo calls (both coded S). In June-Aug keep an ear out for juvenile hissing sounds (code as FL).

Great Horned Owl 

  • Map of atlas records
  • Habitat
    • Open areas (e.g., fields, marshes) near mature forest
  • Time of night
    • Most vocal for an hour after dark and an hour before dawn
  • Key tips, sounds, and behaviors

Barred Owl 

  • Map of atlas records
  • Habitat
    • Dense deciduous or mixed forest, particularly near water
  • Time of night
    • Throughout the night
  • Key tips, sounds, and behaviors
    • Common Barred Owl noises are “who-cooks-for-you” song and “hoo-ahhh” call. This species will duet, qualifying as a “C” code. The juveniles also make a diagnostic begging noise, a high-pitched raspy hiss which differs quite a bit from Great Horned’s begging. This is another automatic “FL” confirmation if you know which block it’s coming from, and can sometimes be heard during the day.


Long-eared Owl 

  • Map of atlas records
  • Habitat
    • Open forests, marshy areas, and dense coniferous woods (e.g., red cedar thickets) near open natural fields
  • Time of night
    • From shortly after dusk throughout the night
  • Key tips, sounds, and behaviors
    • Long-eared Owls are hard to see, don’t vocalize often, use a variety of habitats, and are unpredictable. The male song is a low-pitched series of “hoo” notes (code as S), given every few seconds and similar to the sound of blowing across a bottle. The male’s hoots can be heard over large distances, in contrast to the soft female nest call (given by the female at the nest; code as ON). Perhaps the easiest way to confirm this species is by listening for the distinctive juvenile begging call (code with FL). Caution: distant barking dogs or mooing cows can sound like Long-eared Owls at times. For more tips, read this article about Long-eareds in Vermont.

Northern Saw-whet Owl 

  • Map of atlas records
  • Habitat
    • Swamps (red maple, tamarack), and forests with many snags (ideally conifer)
  • Time of night
    • Calling peaks at 2 h after sunset and decreases until just before sunrise.
  • Key tips, sounds, and behaviors

May-July Focal Species

 

Pied-billed Grebe 

  • Map of atlas records
  • Habitat
    • Marshes and ponds with emergent vegetation
  • Time of night
    • All night
  • Key tips, sounds, and behaviors
    • Listen for the loud, whooping cuckoo-like song (code as S). Sometimes a pair will sing together in a duet (code as C). Calls are more of a chatter and can also be given simultaneously by the pair in a duet (code as C).

Common Nighthawk

  • Map of atlas records
  • Habitat
    • Sandy soils (e.g., pine barrens habitats)
  • Time of night
    • Dawn and dusk with visible moon
  • Key tips, sounds, and behaviors
    • Nighthawks give a peent sound (code as S) very similar to that of an American Woodcock, different in that it’s raspier, descending at the end, and comes from the air rather than the ground. Courtship display of rapid dives creates a booming sound as air passes over wings (code as C).

Chuck-will’s-widow 

  • Map of atlas records
  • Habitat
    • Pine barrens, edges of swamps
  • Time of night
    • Dawn and dusk with a visible moon
  • Key tips, sounds, and behaviors
    • Habits of this bird are similar to Eastern Whip-poor-will. Listen for “chuck-will’s-widow” song. Males sing with greatest intensity in Apr-May, quiet down in June, and sing more again later in July and August. On days of full or near-full moon, singing may continue all night. If it’s warmer, they sing more. Code this song as S.

Eastern Whip-poor-will 

  • Map of atlas records
  • Habitat
    • Pine barrens, also forest openings such as fields, quarries, and power-line cuts
  • Time of night
    • Dawn and dusk with a visible moon (ideally when at least half a moon is visible)
  • Key tips, sounds, and behaviors
    • The namesake “whip-poor-will” song is the best way to detect this species. Code their song as S. Outside of that, watch roads in sandy habitats for ‘eyeshine’ reflecting in headlights.

Virginia Rail

  • Map of atlas records
  • Habitat
    • Broad array of wetlands with any patch of cattails larger than a swimming pool
  • Time of night
    • Throughout
  • Key tips, sounds, and behaviors
    • Virginia Rails can be heard any time of day or night. Virginia Rails can be coded as “S” when hearing their “kiddick” calls. When out birding in marshes, you’ll often hear the “grunt” calls of Virginia Rails, which can be coded as “H” as they are used in communication between mates.

Sora 

  • Map of atlas records
  • Habitat
    • Wetlands containing cattails and with patches of open water
  • Time of night
    • Dawn and dusk
  • Key tips, sounds, and behaviors
    • Sora’s descending “whinny” call is heard often, used by mated pairs and when birds are establishing territories. Their other well-known call is the “ker-wee,” which is likely used to attract mates. Both calls are coded as S.

Clapper Rail

  • Map of atlas records
  • Habitat
    • Extensive saltmarshes
  • Time of night
    • Dawn and dusk
  • Key tips, sounds, and behaviors
    • Listen for the male’s repeated “kek” calls in marshes on Long Island (code as S). Their grunt or “clapper” calls are used by paired birds and should be coded as C. Code other calls as H.

Common Gallinule 

  • Map of atlas records
  • Habitat
    • Freshwater wetlands with open water and emergent vegetation
  • Time of night
    • Mostly at dawn, secondarily at dusk, rarely at night
  • Key tips, sounds, and behaviors

American Coot

  • Map of atlas records
  • Habitat
    • Freshwater wetlands with open water and emergent vegetation
  • Time of night
    • Dawn and dusk
  • Key tips, sounds, and behaviors
    • Most frequent calls a sharp “poot”, and a screeching “kree”. Coots are also particularly noisy swimmers so you may hear splashing water.

American Bittern 

  • Map of atlas records
  • Habitat
    • Large cattail or sedge marshes, wet meadows
  • Time of night
    • Throughout night
  • Key tips, sounds, and behaviors
    • American Bitterns have one of the most unique bird sounds, often referred to as “thunderpumpers.” Their main call is the thunderpumping “pump-er-lunk” (coded as S). They call less frequently under high winds and cloud cover.

Least Bittern 

  • Map of atlas records
  • Habitat
    • Extensive cattail marshes, especially with channels or open patches
  • Time of night
    • Dawn and dusk
  • Key tips, sounds, and behaviors
    • Males give a soft “coo-coo-coo” call (coded as S). They also give a few other vocalizations, most frequently the “reek-reek-reek” call, which should be coded as H. They’re easier to find in July, when juveniles are active and family groups can be seen and heard. More active at dawn and less vocal in windy or rainy conditions.

Atlas safely at night

Being out after dark poses additional challenges that might be different from what you’re used to. Here are some suggestions for nocturnal atlasing:

  • Stop safely. Park fully off the road in a safe place, keep an eye out for traffic (put your hazards on if you feel you need it), and make sure you’re visible to any passing vehicles.
  • Consider teaming up. Heading out with a buddy often helps you hear more birds, maximize safety, and navigate at night!
  • Scout during the daytime. Check out habitats, access, and parking spots during the daytime.

Please only atlas at night if you feel comfortable doing so.