In Part III here, we focus on the primary target species of nocturnal atlasing, including the owls, nightjars, American Woodcock, and Wilson’s Snipe.
Index to our Nocturnal Atlasing series:
Great Horned Owl
This is the earliest species that can be atlased, with breeding behavior beginning mid-winter. Often in winter or spring a pair will sing in duet, the two alternating calls to each other and males having the deeper tone/voice. These duets can be coded as the “P” code. In summer, it’s a good idea to learn the juvenile begging call, which if often confused with calls of the extremely rare Barn Owl. This is unique to dependent juveniles so as long as you aren’t close to block lines, hearing this is an automatic “FL” confirmation. This species does not respond consistently to playback, which is not recommended since they are a predator of other owls. Great Horneds are found in a variety of woodlands as well as suburbs or even urban areas with large trees.
Barred Owl noises vary from the classic “who-cooks-for-you” to shorter calls in the same pitch (see below) and they become more vocal by early spring, when they can be coded. Be sure not to confuse the single “hoo” notes with those of the rarer Long-eared Owl. Just like Great Horned, this species will duet, qualifying as a “P” code. The juveniles also make a diagnostic begging noise, a high-pitched raspy hiss which differs quite a bit from Great Horned’s begging (see below). This is another automatic “FL” confirmation if you know which block it’s coming from, and can even be heard during the day sometimes. This species sometimes responds to playback or voice-imitations of the “who-cooks-for-you” call. Deciduous or mixed forest is best, especially near water.
A familiar resident of southern and central Wisconsin hardwoods (see WBBA I range here), this owl is also rather easy to identify by call (though compare the alternate song with the snipe display-flight winnow). Screech-Owls can be heard throughout the night in medium-sized or small woodlots or even neighborhoods with a few large trees. This species is very responsive to playback or a well-performed whistle. Keep an eye out above you while doing playback because they’ll frequently fly in silently to investigate without calling back. Like Barred Owls, they get more vocal as spring nears, when breeding activity commences.
Northern Saw-whet Owl
This owl is quite vocal during calm spring nights, especially in the northern half of the state (see WBBA I range here). Areas of conifer tend to be best, especially the edges of swamps or stream corridors. Because they are vocal south of their breeding range, we need to pay attention to the Breeding Guideline Bar Chart during spring, especially in the southern half of the state. This species is also quite responsive to playback or whistles although its responses differ. Sometimes the tooting song or a wail call will follow and other times the response will be barks or bill snaps, which are aggressive territorial responses that can be coded as “T” probable. Beware that there are several non-bird sounds that sound like Saw-whets including Spring Peepers and distant trucks in reverse.
This is the most mysterious and least-understood of our owls, and possibly of all Wisconsin breeding bird species. They are hard to see, don’t vocalize often, use a variety of habitats, and in general are quite unpredictable. For breeding they generally require a mix of forested and open habitats so check areas of dense conifer (such as cedar or young pine groves) or dense deciduous brush near open fields anywhere in the state. This species occasionally answers playback but often does not. They also make some unusual and sometimes bizarre calls, especially following playback. Beware that distant barking dogs or mooing cows can sound like the hooting song of Long-eared Owls at times.
Unlike the owls above, this grassland owl is much more often seen than heard. Most active at dusk and dawn, watch for their moth-like flight over the same areas that Northern Harriers patrol by day. Hearing them at night is rare, and unless you’re close to a large grassland you should not assume that anything you hear reminiscent of the barking noise of this species is indeed a Short-eared call. The best way to try to atlas this species is to scan for foraging owls in large grasslands or sedge marshes during twilight. Their known breeding range in the state is limited to central and northern Wisconsin (see WBBA I range here). This species is also later than the others and should not be coded before May in most cases.
A reminder about coding owls
For all owl species, remember that the primary vocalization functions as their song so should be coded “S”. Secondary call notes should be coded as “C” but these are usually rare. If the owl has responded to another owl or a tape aggressively (bill snapping or other very abnormal repeated calls), the “T” code can be used, otherwise response to playback should be given the “S” code. When you find owls, remember to check back in a week or more to try to hear them again to upgrade to the “S7” probable code.
Breeding Guideline Bar Chart for Owls
Below is the owl portion of the Breeding Guideline Bar Chart. Don’t code these species too early, even though they also vocalize in winter. This is because we cannot be certain they’re on their breeding territories, especially Saw-whet, Long-eared, and Short-eared Owls which are highly migratory. If you are wondering if your bird is a migrant or breeder, consult this chart and if you still aren’t sure, ask!
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While Eastern Whip-poor-wills have sharply declined in some areas, their well-known song is still commonly heard in areas with dry soils statewide, usually represented by pines or oaks. They return to the state in late April and are locally common until they become quiet in late summer. They’re much more vocal than owls so they often can be coded as probable “M” where good populations exist. Cover as much ground as you can in your block during twilight or a night with a moon and if there aren’t enough to reach “M”, this species can easily be “S7’d” if you return a week or more after your first detection. Watch the roads while driving because their eyeshine is obvious and gravel or sand roads can be a favorite singing location. Occasionally a pair will sit on the road together, warranting a “P” code.
Nighthawks are also most easily found during twilight or any time with a visible moon and favor sandy soils statewide, especially barrens habitats. They also nest in cities of varying population size that have flat-topped gravel roofs, though their numbers have declined there in recent decades. Small numbers also breed in large grasslands or other open areas with rock outcrops or other exposed ground for nesting. There are several relatively easy ways to get this species to probable, including “M”, “S7” and “C”. Their courtship display is easy to hear and identify on breeding territories, see the “booming” recording below. Beware that this species is a late spring (late May even into early June) and early fall (beginning mid-August) migrant so seeing them hunting in the daylight hours during these times does not mean they’re on territory.
The habits of this bird are very similar to whip-poor-will. This is a rare species in Wisconsin but they do occasionally stray north of their typical range in the southern U.S. Currently, there is only one known location in the Southern Kettle Moraine State Forest but there may be a few more out there. Can you find the next one!? If you do, please provide detailed comments in your eBird checklist and try to obtain a recording if possible. Although singing birds have been recorded, breeding for this species has never been documented in the state.
Breeding Guideline Bar Chart for Nightjars
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Since the nightjars are highly migratory, be sure not to code them too early or too late. This is especially an issue with nighthawks, which are highly-detectable and sometimes vocalize on migration.
The American Woodcock is another bird that’s very hard to find during daylight hours but easy to code while nocturnally atlasing. In young forests and field/forest edges, “peenting” (the song – coded “S”) begins about 20 minutes after sunset and intensifies for the rest of twilight. The twittering aerial display flight is the “C” code. The “peenting” and displaying goes until it is pitch dark out and can last longer (sometimes through the night in spring) with the presence of a moon. Not an evening person? Woodcocks are just as active toward dawn so that works too! The peenting of Amer. Woodcock, given from the ground in the spring, is often confused with the similar call of the C. Nighthawk, which is given from the air later in the year, so be sure not to confuse them.
The habits of this species are similar to American Woodcock, with some differences. Unlike woodcock, snipe are always near water, usually a wetland containing sedge or other grasses. A vegetated flooded field or wet shrubby marsh is fine as well. The “tuk-tuk” call, given from the ground, acts as the song and can be heard much farther from sunset or sunrise than the “peenting” of the woodcock. The winnowing display flight is a “C” code. This also starts earlier in the evening and ends later in the morning than Woodcock display flights. Like woodcock, snipes can be heard vocalizing and sometimes displaying throughout a night with a moon in spring.
Breeding Guideline Bar Chart for Woodcock & Snipe
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Since woodcock and snipe can display during migration, be sure to wait until the correct time to code these species. See their portion of the Breeding Guideline Bar Chart for assistance.
Below is the portion of the Acceptable Breeding Codes Chart for these species. This is another great resource to consult when deciding how to code an observation. The lower the number on the chart, the better the code fits the species. If using code 3 or 4, please provide thorough details with your observation in Atlas eBird.
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Stay tuned for a bonus Part IV of the series which will focus on even more birds that can be detected during your nocturnal atlasing, including marsh birds, rare sparrows, and more, as well as other Wisconsin night sounds such as frogs and mammals.
Eastern Whip-poor-will photo by Ryan Brady, all others by Tom Prestby