Forecast and Analysis

Migration Forecast: 17 – 23 March 2012

Andrew Farnsworth The Cornell Lab Mar 17, 2012

Expect another week of record early arrivals and large numbers of migrants across much of the continent. Mild conditions will dominate away from the far west where unsettled weather will continue. A large high pressure system will once again become the dominant weather system through almost the entire forecast period with a prolonged period of southerly winds stretching from the Rockies to the East Coast. The Pacific Northwest will continue to see one low pressure system after another marching in off the ocean, with stormy conditions the general rule. Even the normally dry Southwest could see a low pressure system and precipitation early next week before returning to more tranquil weather. This low pressure system will move into the central U.S by the middle of the week with unsettled weather likely.

Links to species names below take you to the March eBird maps for 2012. Daily forecast maps are available here.

Expect large numbers of Ring-necked Ducks this week across much of the continent

Expect large numbers of Ring-necked Ducks this week across much of the continent

Ring-necked Duck

Duck migration is in full swing and we expect Ring-necked Ducks to be reported from more locations and more frequently across the Lower 48 than in any other week of the year. Unlike other divers, Ring-necked Ducks are often found in spring migration on relatively small ponds and wetlands even in relatively wooded habitats. While concentrations of hundreds and even thousands of birds are possible in certain locales, the species is typically encountered in most of the continent in smaller flocks. The warm southerly winds this week may even take Ring-necked Ducks into Canada’s prairie provinces. Watch for courtship displays and pair formation which takes place during migration. Consider recording ratios of males to female since males often outnumber females. Separating adults from 1st-spring birds is more difficult than many other Aythya, in part because of the relatively early molt.


The Northwest continues to get battered by storms, making significant landbird movements into this area unlikely; some exceptions may occur depending on the timing of the arrival of new storms. If nocturnal conditions are rain-free, light migration may be apparent in some areas. A different situation is likely for much of the Southwest and portions of the Great Basin and the Rockies, where light winds early in the forecast period should facilitate movements. By Sunday and Monday, the increasing threat of precipitation will likely shut down movements in many areas; however, by later in the week, in between eastward-moving instabilities, conditions may again become favorable for movements of birds into these areas. In areas where migration is apparent on radar (e.g., no precipitation, no extensive mountain blockage), we expect reflectivity values of 5-10 dBZ (approximating 50-70 birds km-3).

  • Strong onshore flow from central California northward over the weekend could result in excellent seawatching conditions. Look for loons and phalaropes to be on the move, as well as gulls and alcids. A mega to watch for is Mottled Petrel, exceptionally rare from shore.
  • Expect the first White-throated Swifts to return to breeding locales in the southern Rocky Mountains as far north as Colorado and Utah, perhaps even into Washington. White-throated Swifts typically return during early April to Montana, so it will be interesting to see if the warm southerly flow will result in earlier arrivals.
  • Sage Sparrow migration should be in full swing throughout most of the Interior West. The second half of March through early April is the best time to find this species as a migrant and also slightly out of range. Strays are often found during snowstorms, quite often within a hundred meters or so of a reservoir or interior lake. Watch for them running along the ground with their tail cocked.
  • Turkey Vultures should be on the move across the interior west with light winds and warm temperatures promoting good soaring conditions. Expect to see numbers return to the Great Basin this week.
  • Say’s Phoebes should return to many areas west of the Rockies this week, but it’s still a bit early to see migration on the northern Great Plains. Will the warm southerly winds across the plains move Say’s early this year?
  • Elf Owls should return to Arizona and Texas this week, perhaps vocalizing in the calm, warm nights ahead.
  • Cassin’s and Western Kingbirds should appear in numbers across the Southwest this week, along with a suite of passerines including Bell’s VireoLucy’sYellow, and Wilson’s Warblers.

Great Plains

Southerly flow for the early portion of the forecast period should facilitate movements of many species, both diurnal and nocturnal. By Monday and Tuesday, with the threat of more extensive and intense precipitation associated with the approach of low pressure, more northerly portions of the Plains will likely see movements dwindle, although more southerly areas could see potentially interesting conditions to concentrate migrants. The end of the week is forecast to be rather different, with potentially favorable conditions in the more northerly portions of the region including the border-states. For those watching radar, we expect nocturnal movements in the 5-20 dBZ range (approximating 50-250 birds km-3), with heavier migration in areas with southerly flow that do not have precipitation.

  • Goose and duck migration should continue in full swing throughout the region. Observers in northern regions should watch for a continuing influx of waterfowl with numbers of most geese peaking in the Dakotas. The strong southerly flow should produce early arrival dates for several species of waterfowl inSaskatchewan and Manitoba.
  • Franklin’s Gulls should appear throughout the Great Plains this week, with generally isolated occurrences in the Dakotas and widespread in Texas. These will mostly be individuals and small flocks of single digits but birders in Texas may see flocks into the low hundreds. We expect the pattern of warm southerly flow to carry them as far northeast as Wisconsin and Minnesota and observers farther east are advised to watch for this species.
  • Watch for American Golden-Plover from Texas north to Kansas as far east as staging grounds in Illinois and Indiana.
  • Raptors should continue to move through the northern Great Plains, with Red-tailed HawkRough-legged Hawk, and Bald Eagle dominating the mix; watch for American Kestrel too. Watch for Red-shouldered Hawks in easternmost portions of the Great Plains.

Upper Midwest and Northeast

The Upper Midwest should see favorable migration conditions continue into the middle of the week and beyond, particularly in the Great Lakes region. Southerly flow should continue to bring diurnal and nocturnal migrants into the area, and it is not until late in the week that forecasts for more extensive precipitation may produce unfavorable conditions for movements. By the beginning of the week, conditions in many areas of the Northeast will start to become more favorable for movements, and by mid-week many areas should see similar movements. Scattered early week precipitation may warrant checking local inland water bodies and migrant traps, depending on the extent and duration of the precipitation. We expect nocturnal movements on radar to appear primarily in the 5-15 dBZ range (approximating 50-100 birds km-3), with perhaps a few areas of locally higher migration amounts (e.g. 20 dBZ, approximating 250 birds km-3).

  • Eastern Phoebes are already arriving on record early dates and with unprecedented numbers of early individuals, including eBird reports from as far north of Kingston, Ontario and Door County, Wisconsin. Already, 10% of checklists in Cook County, Illinois are reporting this species. During the previous ten years, less than 3% of checklists reported this species during the second week of March (see details). Expect large numbers to continue north.
  • The strong southerly flow may make this the last good week to detect Rough-legged Hawk and Golden Eagle in significant numbers. This should be an excellent week for migrant Red-shouldered Hawks.
  • American Woodcocks have returned to breeding grounds throughout the US and this week may offer some of the best woodcock watching of the year. Few activities in March compare to watching woodcocks display—consider taking a non-eBirding friend to watch these amazing displays as an introduction to birding. When you’re done, be sure to share your eBird checklists with them. Pick a quiet and warm evening to check likely habitat where old fields and woodlands mix. Listen for this species’ distinctive peenting and wild aerial displays. Return to old sites to see if this declining species has returned. Remember, it’s just as important to submit checklists from where you don’t find them.
  • Expect continuing good numbers of early migrant sparrow with strong influx ofSong SparrowsFox Sparrows and Slate-colored Juncos along with the first Swamp Sparrows.
  • Watch for American Golden-Plover in Illinois and Indiana.

Gulf Coast and Southeast

Early week conditions along the Gulf Coast should provide a continued pipeline for early trans-Gulf and circum-Gulf migrants to move. By midweek, an interesting possibility of precipitation and wind shift with frontal passage in coastal areas may provide an opportunity for nice early-migrant fallout conditions in coastal hotspots. Birders watching radar should look for trans-Gulf type fallouts if conditions in which precipitation or apparent wind changes approach or pass coastal areas by morning or midday, but circum-Gulf type fallouts if such conditions occur late in the day or during the course of the night. Even areas without wind shift may see interesting birding, depending on the extent of precipitation associated with the movement of the system eastward. As high pressure establishes itself off the Atlantic Coast later in the week, conditions in the Southeast could become increasingly favorable to see an influx of early Caribbean migrants, depending on the presence and extent of precipitation. Nocturnal movements on radar should appear in the 5-15 dBZ range (approximating 50-100 birds km-3).

Posted 16 March 2012 by Christopher Wood, Andrew Farnsworth, Marshall Iliff, and Brian Sullivan of the Cornell Lab of Ornithology and David Nicosia of NOAA, on behalf of Team eBird and BirdCast.