The warmer temperatures in February and the start of this month led to Six Mile Lake being completely open a week ago, the earliest “ice out” date even longtime residents can remember. In contrast, the ice lingered into May last year and normally in March would only have pools available where the creeks feed in and out of the lake.

So much open water so soon could be expected to draw the flocks of waterfowl north at a quicker pace, taking advantage of the more favorable conditions. But at least for now, numbers have been scant — a couple Canada geese, some common mergansers, a pair of mallards.

While the region might seem ready, other factors have to come into play to hinder even the earliest migrants advancing northward. This week and into next for now do not have that right combination of decent warmth and, more importantly, a good southwest wind, said Ryan Brady, a conservation biologist with the Wisconsin Department of Natural Resources.

This recent cold turn and the return of snow cover — along with winds from the north — seems to have stopped much of the early movement, he said. Even southern Wisconsin isn’t seeing much in the way of great numbers of waterfowl. Air flow has not been conducive for good flying.

By the time this cold turn passes, migration might be back on its normal schedule — which isn’t a bad thing, he said. Migration times for many bird species are synchronized with what might be the favored food source being available. If strict insect-eaters such as swallows arrive before the bugs are out in good numbers, it could be a fatal mistake.

Which is why the seed-eaters or those that can at least tolerate a more varied diet are usually the first to arrive in late winter or early spring, Brady said. And that has happened — the only early birds that appear back in numbers are red-winged blackbirds and common grackles.

These two species are more than willing to take advantage of the generosity of backyard bird feeders to get through if the fickle weather of late winter-early spring take a bad turn.

These birds race back early, often when snow and ice remain, with the aim of staking claim to the prime nesting areas. They already can be heard issuing challenges from the edges of wetlands.

Yet these early birds — almost entirely males, usually of breeding age — will cease the trash talk at this time of the year when coming into feeders, said Laura Erickson, an avian expert and author who has a long-running public radio program “For the Birds” and blog of the same name at https://www.lauraerickson.com/.

Red-winged blackbirds will tuck those famous shoulder epaulets in. Common grackles will not posture, fluff out feathers or otherwise display. “They don’t want anyone attacking them while they’re getting food,” she explained.

That behavior will change as temperatures warm, insects emerge and hormone levels rise in these males — especially when the females finally show up, migrating much later, she said.

Because it’s the females that will size up which males have established the best territories and are worthy of letting them sire their broods for the season. So later in the spring, the males will ramp up the calls, the posing and squaring up with other males.

Right now, it’s not necessary to be confrontational, Erickson said.

American robins have returned as well. They have the ability to turn to fruit and berries if the ground is covered or too frozen to reach worms, grubs or other prey, Brady said. But this late in the winter, pickings might be slim, as other birds like waxwings consume fruit as well.

Those who feed birds can help by putting out live or dried mealworms, chopped fruit or berries, even sunflower chips the robins can turn to when snow and cold make other options scarce, Brady said.

He’s concerned the cold and snow will persist long enough to potentially harm woodcock, which also are back and need open ground to probe for food. But woodcock in most years return so early they risk being caught out if winter re-establishes itself, he said.

“This is what shapes migration … the early bird does not always get the worm,” Brady said.

For most migratory birds, however, this kind of weather in late March is not nearly as potentially dangerous as April snowstorms for species that never otherwise cope with such conditions, he said.

So better to have a cold spell put the brakes on migration now rather than later.

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.