So, are these ducks possible breeders yet? Photo by Joel Trick.
Last week we ran a feature on understanding breeding codes and use of the Breeding Guideline Bar Chart (.pdf version, .xls version). Here we’ll explore what species are breeding as of early April, but just as important, we’ll explore what birds just returned to the state that aren’t yet safely recorded as breeding.
To review, here’s what should be breeding the first week of April, based on data from the first Atlas, statewide research projects, and bird experts across the region.
If you need a refresher on how to interpret this chart, refer to last week’s breeding code post. Over a dozen species are squarely in “B” now on the chart and could be getting at least low-level breeding codes (such as “H” for suitable habitat) almost every time you see them. These include some familiar town birds like Rock Pigeon, Mourning Dove, and House Sparrow, as well as more elusive resident galliformes (chicken-like birds) such as Spruce Grouse, Sharp-tailed Grouse, and Greater Prairie-Chicken. Virtually all owl species are also nesting now, from the common Great Horned, Barred, and E. Screech to the Great Gray, Boreal, and N. Hawk Owls very rarely found across the north. Other notoriously early breeders include Common Raven, Horned Lark, and the boreal forest-dwelling Gray Jay.
However, while B means you should consider giving a species at least a low-level code every time you encounter it, it’s not a complete green light to stop asking yourself questions about suitable habitat and behavior. If you saw a flock of pigeons fly over in deep woods, you would probably still not want to give them a code because it is unlikely they would be nesting near your current location. On the other hand, a pair of birds hanging out by a farm silo or urban building day after day certainly deserves a Probable breeding code this time of year.
The bar chart indicates several dozen additional species in ”E” right now, for which you need to use careful observation and your local knowledge before assigning breeding codes. These include more backyard favorites (e.g. Black-capped Chickadee, White-breasted Nuthatch, Northern Cardinal, American Robin, House Finch), more galliformes (e.g. Ruffed Grouse, Wild Turkey, Ring-necked Pheasant), more owls (Long-eared), some waterbirds (Canada Goose, Mallard, Great Blue Heron), several raptor species (e.g. Bald Eagle, Red-shouldered Hawk, Cooper’s Hawk), and others.
A good example of the need for caution comes from our first flycatcher to arrive each spring, the Eastern Phoebe. Phoebes are largely migrating through the state right now, and in general will not demonstrate obvious breeding behaviors this early in the season. However, if you had a bird hanging for several days around your shed where they nested last year, you could certainly code them as H, or higher depending on behaviors you observed. Although the Breeding Guideline Bar Chart somewhat gives the impression that all the migrants come through before the breeding birds arrive, in some cases, territorial birds can come right back and sometimes the first bird of a species you see will actually be the male back on his old territory. During this time of year when there is a gray area, it’s up to you to use repeated visits, local knowledge, and study of behavior to decide if you observed a bird on territory or just a migrant. Red-winged Blackbirds singing persistently from cattails are probably on territory — a mixed flock of blackbirds foraging on a lawn are probably not. Remember, you can always go back and edit an eBird checklist later if you find out you made the wrong call — this is another reason to record good notes on behavior in the species Comments field when entering birds in borderline situations early in the season.
Please leave comments on breeding records, especially early in the season to indicate why you felt the species was likely showing breeding behavior. This will help us refine the bar chart in future years.
Here is a quick series of examples of how different situations might cause you to treat the same species on the same date differently (assume this is early April in central Wisconsin):
Single Horned Lark on plowed field: Possible – H Suitable habitat
Pair of Horned Larks together on plowed field: Probable – P Pair
Horned Lark with mouthful of grass: Confirmed – CN Carrying nest material
Flock of Horned Larks on plowed field: Likely migrants, no code
Single Horned Lark on beach: Likely migrant, no code
Pitfall: waterfowl
Based on early data submissions, perhaps the biggest pitfall right now is waterfowl. The bar chart shows E for Canada Goose, Mute Swan, and Mallard right now. But most waterfowl are paired up. So is that Probable P – Pair? Some of them are doing displays – is that Probable C – Courtship? But wait — ducks that are very rare breeders in the state, like Common Goldeneye and Lesser Scaup, are also paired up and performing displays. If you check the Breeding Guideline Bar Chart, you see that Common Goldeneye and Lesser Scaup don’t turn to E until the last week of May and B until the second week of June. The take-home is that waterfowl often pair up and show breeding behaviors far from where they will actually nest. The implication for your Canada Geese and Mallards is to be patient because it’s hard to tell a migrant pair of Canada Geese from your local nesting pair of Canada Geese. Trust us, if the Canada Geese hatch young, you’ll confirm them in due time.
Pitfall – Commonly-observed birds that aren’t nesting now or won’t nest near the point of observation
Quite a few species have now returned, and are resident in your area all summer but it may be difficult to tell if they are breeding or not. For example, right now you could head to a local lake and see hundreds of gulls and cormorants, 5 Bald Eagles standing on the ice, and 15 American crows picking in the sand. But none of those individuals may nest in your block! They might be foraging there, they might be roosting there, and/or they might be migrants. As the bar chart turns from M to E to B for more species in the coming weeks, you should always be asking yourself: Is this a likely breeding situation? Are the birds in appropriate habitat? Are the birds displaying behaviors consistent with a nesting pair? Some birds, like gulls, herons, egrets and cormorants, habitually loaf and forage well away from breeding colonies. Raptors have large home ranges that may span several atlas blocks. And some shorebirds, waterfowl, and songbirds will spend their summers in places they have no intention of nesting!
But don’t let the exceptions discourage you. The Breeding Guideline Bar Chart and your local knowledge should provide good guidance. Understanding birds within a broad and local context is extremely helpful, and hopefully something to be learned through your participation in the Atlas. It also pays to be patient by making repeated/later visits to strengthen your observations. Also be sure to include good notes describing the situation in your eBird comments for later evaluation. Just do your best at assigning birds to breeding codes as you see fit, and when the season is over we can screen all the data to re-assess records with the value of hindsight and broader perspective. Last but not least, if you have a question about a particular situation, ask and receive a prompt reply at our Discussion Forum.
Itching to get out in the field for some early spring birding? Here’s the first chart broken down into groups to help you see habitats and species you might want to go after soon.
Backyard/Suburban Species
Waterbirds (be careful, as mentioned above!)
Hawks and Owls
Grouse
There’s actually another group starting to breed right now, and that’s the residents of boreal conifer swamps. Stay tuned for a Species Survey Strategy profile on that group later this week.
Happy atlasing!