Summary of 2016 Atlas Point Counts

You may have heard that we are also running point count surveys as part of the atlas. In this article we introduce this wing of the atlas effort, explain how it’s gathering critical information for conservation efforts in the state, and report on some very preliminary results from 2016.

What is a point count?

Point Counts are bird surveys conducted at a single stationary location. Observers stand in one spot for a fixed period of time (in our case, 10 minutes), and record all the birds they detect. Counts are typically aimed at songbirds and conducted in early morning during the breeding season, so the majority of birds are detected by ear.

Why do point counts?

The atlas is already doing an excellent job filling out maps showing where a species occurs in the state, which is the primary goal of most atlas projects. But what the atlas doesn’t do as well is determine where within that distribution a species is most or least abundant. Adding information on relative abundance atop the information collected by general atlasing gives us the strongest picture we’ve ever had about our state’s breeding birds.

Here’s a map of Veery from the first atlas conducted from 1995–2000. It looks like this species occurs across almost the entire state. But is it equally abundant everywhere within that distribution?

Here’s a graphic showing the number of Veery at each point count block in 2016, with bigger, redder circles indicating more Veery.

And here’s a map (often called a “thunderstorm map” for its resemblance to weather radar) showing the relative abundance of Veery within that distribution. Clearly Veery is NOT equally abundant across the state, instead appearing to be much more common in the northwest.

In addition, outputs from models like these can provide population size estimates for many of our breeding bird species, an important component to assessing species status.

One downside of point counts is that if a species is not very detectable during a 10-minute roadside count, it does not get well sampled. So for the most part, we will get very good information on many songbirds, but other birds will often get missed, such as species that don’t call much during daylight (Great Horned Owl, Eastern Whip-poor-will), don’t call much at all (Spruce Grouse, Virginia Rail), are uncommon breeders (Le Conte’s Sparrow, Cape May Warbler), or often occur far from roads (Lincoln’s Sparrow, Acadian Flycatcher). These species will be better sampled through traditional atlasing methods that allow for more time in the field, and more off-road coverage.

How did we do it?

To accomplish the goals of our point count effort, we determined we needed to survey 5 roadside points per block in every other block across the state. That works out to over 16,000 points in more than 500 atlas blocks. And given our project timeline, we had to do it in just four years, meaning we’d need to survey 4000+ points per year!

Within each block to be surveyed, the five points were drawn randomly and moved to the nearest road, with backup points drawn in case the initial points were inaccessible. The overall plan was fairly similar to methodology used in past second bird atlases in Ontario, Pennsylvania, and Ohio.

So in the first year, we assembled a team of 26 trained and certified surveyors (10 expert volunteers, 9 Wisconsin DNR employees, 7 hired hot-shot technicians) and got to work. We followed a regionally-standardized monitoring protocol (Knutson et al. 2008, Landbird Monitoring Protocol for the U.S. Fish and wildlife Service, Midwest and Northeast Regions) and recorded the distance band and minute of first detection for each individual bird.

What did we find?

We conducted 4,037 point counts statewide between May 24 and July 7, and detected 90,838 individual birds of 192 species (not all of them breeders).

The 4,037 points across the state sampled in 2016.

Here are the Top 10 Species Detected on Point Counts, and the number that we detected:

Obviously these are 10 very common species, but they are also species that occupy roadside habitat and are either very visible or sing often.

On the other hand, here is a list of species detected only once on a point count:

This list includes a mix of migrants, rare breeders, birds that breed far from roads, and vagrants. Who would’ve guessed we’d detect as many singing White-winged Doves and Franklin’s Gulls as Gray Jays and Connecticut Warblers?!

During the planning process, we identified that certain songbirds were poorly sampled by existing surveys like the federal Breeding Bird Survey, specifically species inhabiting northern coniferous forest, and southern interior forest. For this reason, we randomly scattered an additional 138 points into northern and southern forest habitats to try to get better information on this group of species. While results were mixed, we did boost the numbers for a few species, which should improve our understanding of their breeding abundance in the state. Here is the list of our targeted forest species, showing how many we found this year on point counts (including the regular and 138 special forest points) — our current estimate is that 25 birds per year is the “magic number” as far as being able to potentially model their distribution.

In contrast to the Veery map, here’s one other preliminary thunderstorm map with a very different pattern — this one for Bobolink, closely tied to grassland areas. Again, these are very preliminary maps, and will continue to be refined as more data come in and we improve the models.

It will be months before we have all of the data checked and preliminary models run. Rest assured after these data are checked and compiled, they will also be dumped into atlas eBird to help fill block totals.  Although the majority of records will be at the Possible code level, most point-counting mornings netted a couple incidental confirmations.

With 3 more years — and 12,000 points — to go, we at Atlas Central are excited to see the results of this project, which will undoubtedly shed new light on the state of Wisconsin’s breeding birds.