Our final installment of the series focuses on the rest of the species you may hear at night, which vocalize during daylight hours as well. Also addressed are common nocturnal non-avian wildlife you may hear while nocturnally atlasing.
Index to our Nocturnal Atlasing series:
IV – More Wisconsin Night Sounds
Marshbirds
We’ll start with a group of nocturnally active marshbirds. These species vocalize during the daytime and are most likely detected in the early morning or late evening, when they should be targeted. If you are planning on targeting the species addressed in part III after sunset, a great method is to begin your outing a little earlier in the evening to target this group. If you cannot make it out in the evening, no worries because they vocalize occasionally at night as well, especially with the aid of playback.
American Bittern
The familiar “song” of the American Bittern is most frequently heard statewide in sedge marshes but also sometimes in cattail-dominated marshes. They prefer large wetlands or clusters of smaller wetlands for breeding. In areas with high populations, they can sometimes reach the “M” probable code, but since the call carries very far, sometimes a mile or more, be sure not to double-count birds. Also, be sure to code the bird to the correct block if you are near a block line. They’re also quite easy to “S7”, with peak calling in May and tapering at the end of the month. They will occasionally respond to playback but uncommonly.
Least Bittern
The soft calls of this secretive marshbird can be confused with cuckoos and frogs so be careful with this identification, especially if habitat does not seem correct. Preferred habitat is cattail marsh with pools of water but they’ll also occasionally use sedge marshes with open water. They seem to be a little more responsive to playback than American Bitterns but are still inconsistent. If you find one, return to the location a week or more later to try for the “S7”probable code. Unlike American Bitterns, their detection increases throughout the summer, peaking when juveniles are active and family groups can be seen or heard communicating with each other in July. Listen for their sharp alarm calls (see below) during this time. Least Bitterns are locally present statewide but are less common in northern Wisconsin.
Sora
One of our most common secretive marshbirds, the Sora inhabits marshes of almost any size of cattail, sedge, or grass statewide. Sometimes they can be found in shrubby wetlands or small rings of wetland vegetation surrounding a pond or lake. Soras are highly responsive to playback and other loud noises, including at night. The “whinny” serves as the song and they have several calls, but be careful identifying them by call if Spring Peepers are present. They become quieter in summer so try to code them in May or June when the “S7” and sometimes even “M” codes are attainable in proper habitat.
Alternate Call (Marsh Wren and Yellow Rail in background)
Virginia Rail
Fairly common but less common than Sora, this statewide species also is found in most wetland types in the state and can be heard any time of day or night. Although they are most common in sedge and cattail marshes of most sizes, they can be found in shrubbier wetlands than Sora typically is. The advertising song is given in spring and grunt calls can be heard throughout spring and summer. They’re very responsive to playback, usually giving the grunt call. The “S7” is again the most common probable code so be sure to return to any locations a week or more after you find originally find them.
Yellow Rail
Yellow Rails are a very rare resident of sedge marshes and bogs, primarily in the northern half of the state (see their WBBA I range here). The rhythmic clicking can’t be easily confused with any bird but can sound like cricket frog, spring peeper, or an insect. This is the most nocturnal marshbird species and is most likely to be heard during twilight or after dark including the middle of the night. If you find this species at a location other than where they’ve been found so far, please provide detailed comments and try to obtain a recording of the song. Also, return a week or more later to increase your breeding code to probable at “S7”. This is a species that undoubtedly breeds in the state, but we are still lacking a confirmation for WBBA II. Playback works – even try tapping rocks together but beware that this is a Threatened Species so use playback judiciously.
King Rail
Another species that is rare but possible, the King Rail can be found in almost any wetland habitat or size, most likely in the southern half of Wisconsin. Although they’re most likely to vocalize in the evening or morning, they can also be heard at night, especially in response to playback. However, beware that the grunt call of the Virginia Rail can sound very deep like a King Rail. Observers are strongly discouraged to make the King Rail identification unless the repeated “kek-kek” or “kek-burr” song is heard. If you find this species, please record details and try to obtain a recording or photo. This species also requires documentation to the WSO Records Committee. This is a species that undoubtedly breeds in the state, but we are still lacking a confirmation for WBBA II. Most sightings in the state come from wetlands in the Southeast Glacial Plain (roughly the southeast quarter of the state).
Breeding Guideline Bar Chart for Marshbirds
Since these marshbirds are highly migratory and vocal during migration (especially rails), be sure to consult the Breeding Guideline Bar Chart before coding in spring. All species are safe to code starting in late May, and can be coded with observer discretion before then during the “E” period when overlap between migrants and local nesters occurs.
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Nocturnally-active sparrows
Le Conte’s Sparrow
Finally, several Ammodramus sparrow species are known for vocalizing at night as much or more than during the day. The highly nocturnal Le Conte’s Sparrow has a soft buzzy song that sounds like an insect more than anything else. Be careful of alternate abbreviated Savannah Sparrow or Grasshopper Sparrow songs that can sound surprisingly similar. Le Conte’s are most likely to be found in the northern quarter of the state (with some exceptions in ideal habitat in central Wisconsin) in large sedge marshes or floating bogs (See their WBBA I range here). However, they can also be found in wet or sometimes dry hayfields. This is a species that undoubtedly breeds in the state, but we are still lacking a confirmation for WBBA II. In fact, out of all the species that still lack confirmations, this is the most likely one left to be confirmed. The most likely way to confirm this secretive species is probably to stake out an area where a male is singing on territory and patiently watch for adults carrying food.
Song (with Clay-colored Sparrow in background)
Henslow’s Sparrow
This is another sparrow that calls throughout the night during the spring. They prefer drier habitat than Le Conte’s Sparrows, usually grasslands with a dense litter layer, but are also occasionally found in wetter habitats such as flooded hayfields or sedge marshes. Their soft song is easier to hear at night when it doesn’t compete with louder diurnal passerines but they are much more vocal during daylight hours than Le Conte’s or Nelson’s Sparrow.
Nelson’s Sparrow
This is the rarest breeding sparrow in Wisconsin. They are quite vocal at night, possibly even more so than morning or evening. This soft hiccup-like song can be hard to make out even when there is no other noise competition and it can be confused with a short rendition of Savannah Sparrow, which often shares habitat. They’re most likely to be found in large sedge marshes. Please provide detailed comments if you find one of these and please try to obtain a recording if away from the one known state population in the Crex Meadows area. This is a species that undoubtedly breeds in the state, but we are still lacking a confirmation for WBBA II.
Acceptable Breeding Codes Chart
Below is the portion of the Acceptable Breeding Codes Chart for these species. Remember that the easiest way to get this group of species to probable is with the “S7” code, so after detecting them, don’t forget to return to the location at least a week later to try again. This is another great resource to consult when deciding what code to assign to an observation. The lower the number on the chart, the better the code fits the species. If entering a code that is a 3 or 4 on the chart, please provide thorough details with your observation.
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Others
If you’re starting to think there are quite a few species active at night, you’re right, and we haven’t even covered all of them yet, either! A handful of bird species that sing regularly during the day can still be heard at night. None of these are species you’d really target at night, but we include them here to help you figure out what you might be hearing.
Common Loons (Night song/wails) make quite a bit of noise at night but since their call carries a long distance, make sure the lake it’s calling from is in the block you think it is. Pied-billed (Call, Song), and Red-necked (Song) Grebes also make noise at night, the latter is much less commonly heard because of its very limited breeding range in the state. Both species are most likely to be found near large wetlands with large pools of open water.
Several common passerines that are easily detectable during the day vocalize regularly at night and are likely to be heard during nocturnal surveys. Swamp Sparrows (Song) will occasionally let out some song but Sedge Wrens (Song) and Marsh Wrens (Song) are more consistent nocturnal singers. Thrushes often turn on for a period at dawn or dusk, often giving their distinctive call notes rather than songs: Hermit (whee call note, chup call note), Veery (call note), Wood (call note), Swainson’s (call note). A few species not thought of as night birds also give vocalizations then that are different from their diurnal vocalizations. The Ovenbird has a night flight song that can be heard at or after dusk and Black-billed Cuckoos can be regularly found at night. Knowing that hearing this call of theirs is a possibility when birding nocturnally near their habitat is useful for the keen nocturnal birder.
Very rare birds
There are several very rare owls and marshbirds that vocalize at night that are very unlikely to be found during the Atlas but possible. These include Great Gray Owl, Barn Owl, Northern Hawk-Owl, Boreal Owl, and Black Rail. If you find any of these species, even without breeding evidence, please report to atlas staff immediately and submit documentation to WSO. Beware that the deep hoots of Long-eared or even Barred Owl are sometimes confused for Great Gray, the winnow of Wilson’s Snipe is sometimes mistaken for Boreal Owl, and, all too commonly, the piercing shrieks of begging juvenile Great Horned Owls are routinely misidentified as Barn Owl.
Frogs
Birds are not the only wildlife to be heard at night. Especially during the spring months, frog songs dominate the nocturnal hours. Each species has a different habitat and seasonal window but from the time the ice melts until the middle of summer, there are usually at least a couple species of frogs calling. Sometimes large concentrations of frogs, especially Spring Peepers, Chorus Frogs, and Wood Frogs in ephemeral ponds or wooded wetlands can be almost deafening. If you run into a spot like this while nocturnally atlasing, move on after enjoying their sounds for a minute because it is very hard to hear any birds over that level of noise. The calls of the most likely frogs to be heard in Wisconsin are below.
Mammals
You might even hear some mammals (besides the common barking of dogs) when out at night. Coyotes (noise) are possible throughout the state and usually howl/yip in a group for a few minutes periodically. Wolves (noise) are possible in the northern third of the state and have a much lower-toned howl and do not yip. If you’re afraid of being out at night with these predators roaming, remember that they are scared of people and that it’s much more likely to be struck by lightning or attacked by a cow than being attacked by either. If you feel uncomfortable, stay close to your car or hold a light with you while walking (which is recommended anyway). Other sounds from mammals that can be heard at night are the alarm snort/wheeze of deer, and high-pitched calls of flying-squirrels.
As you can tell by now, it’s exciting to atlas at night because it’s a new and rarely explored world. So, give it a try and if you like it, help us knock off coverage for multiple blocks in your area. That being said, try not to be discouraged if you go out and find nothing. This is normal too, and still very important data, so just keep covering ground until you find birds or try again a different night. As always, please feel free to contact your County Coordinator or the Atlas staff with questions or post your question in the Facebook Breeding Bird Atlas Photos and Discussion Group or the WBBA II Facebook Page.
King Rail and and Virginia Rail photos by Cynthia Bridge. Yellow Rail photo from allaboutbirds.org. All others by Tom Prestby.