By Sergio Harding
Northern Saw-whet Owl (J.D. Kleopfer)
For this second installment of our ‘Year of the Night Bird’ series, VDWR Avian Biologist, Sergio Harding, shares the story of our smallest and most mysterious owl species…
When it comes to Virginia’s owls, the Eastern Screech-Owl is often thought of as our smallest species. But that distinction really belongs to the Northern Saw-whet Owl, a secretive species about which we still know relatively little in the Commonwealth. What we do know is that Saw-whets migrate through Virginia in the fall, and that this population of migrants can vary significantly from year to year, with ‘irruption’ or ‘invasion’ years seeing particularly high numbers. We also know that Saw-whets winter in Virginia, with numbers again potentially fluctuating between years. Winter and migration data are the result of banding efforts at various locations in the Coastal Plain, Piedmont and Mountains regions of Virginia over the past 15-20 years. However, data on the Saw-whet’s breeding distribution and status in the Commonwealth are scarce. Filling this data gap through the 2nd VA Breeding Bird Atlas (VABBA2), especially in this, its Year of the Night Birds, is a high priority for the bird conservation community at large.
What:
Familiarize yourself with Saw-whet appearance and vocalizations. Its small size serves to distinguish it from all other eastern owls except for Screech-Owls; the rounded facial disk, distinctive facial V pattern, lack of ‘ear’ tufts, and the adult’s broad, vertical streaking (as opposed to horizontal barring) on the breast and belly set it apart from the Screech-Owl. The male’s song is a persistent, high-pitched ‘toot’. Check out Cornell’s All About Birds Saw-whet site for identification tips, images and sound samples (including lesser known vocalizations).
Mist-netted Northern Saw-whet Owl (J. D. Kleopfer)
Where:
We currently only know of spring and summer Saw-whet records from areas west of the Blue Ridge Mountains and, to a lesser extent, the eastern Blue Ridge foothills. Although traditionally believed to be associated exclusively with coniferous habitat, Saw-whets were shown to have a much broader habitat preference during neighboring West Virginia’s own 2nd Breeding Bird Atlas. There they are known to breed in mixed hardwood/coniferous forests, and to a lesser extent in pure hardwood forests. What little is known about breeding Saw-whets here in Virginia suggests the same, with the key being to focus on forested habitat.
When:
Based on survey work conducted in neighboring states, the peak calling period for Saw-whets in North Carolina is roughly late March through early May. Saw-whets in West Virginia actively responded to playback from April through June. Surveys should be conducted at least one hour after sunset. Avoid rainy or windy conditions.
How:
Because relatively little is known about Saw-whet habitat use in Virginia, for maximum efficiency we recommend conducting surveys along driving routes within a block, rather than surveying in only a few patches of potentially suitable habitat. Here is one suggested approach, designed by Doug Gross of the PA Game Commission for use in the 2nd Pennsylvania Breeding Bird Atlas (2nd PA BBA):
- survey at 0.5 mile intervals along a continuous secondary road for up to 8 points per route. Each point should be at a location where it is safe to stop, where there is no significant noise interference (ex. stream), and where there is at least some forested habitat within 150 m (~160 yards, or ~1/10 mile) of the point. Mark the point locations using your phone of GPS unit, if possible.
- Conduct a survey at each point that includes both silent listening periods and playback (male advertising call). Playback is an integral part of Saw-whet surveys as it can greatly increase the detectability of this nocturnal species (although playback is strongly discouraged for general use in the VABBA2, conservative use is recommended for owl surveys). Phones can be used for broadcast, although we recommend broadcasting playback at 50-60 decibels; if a phone is not loud enough, we recommend using external speakers. You can download a playback file with the sequence used for the 2nd PA BBA here. The file ends with a two-minute silent listening period, which we recommend extending to five minutes, as Saw-whets can take some time to respond.
- Note that Saw-whets may approach the site in response to playback, but not call back. It is important that you spend time scanning nearby trees with a light source in order to detect silent owls that may be present. If other species are detected, they should also be noted.
- If surveying for multiple owl species of owls in one area using playback, we recommend starting with Saw-whet, followed by Eastern Screech-Owl, Barred Owl and Great Horned Owl in that order. All three of the larger species are known to prey on Saw-whets, although Barred Owl has the greatest overlap with Saw-whet habitat in their association with heavily forested habitat. If a Saw-whet Owl is detected, DO NOT proceed with playback for the three other owl species. Instead, return on a different date to complete your surveys for the other owls, or move on to a different site well-away from the Saw-whet detection.
Data Entry:
Report your data through the VABBA2 eBird portal. We recommend reporting each survey point separately, as a stationary count. If no owls are detected, you can report this the same way you would report a standard eBird checklist, by not checking any species from the list. Be sure to note in the comments what owl species your surveyed for.