When it comes to food-chain hierarchy, ducks are the rabbits of the avian world — essentially every critter with forward-facing eyes wants a bite of them. The threats are even broader for ducklings, which are consumed by practically anything large enough to complete the task, from bullfrogs to herons. And you can imagine the vulnerability of duck eggs to plundering, given their immobility and tasty, nutrient-rich yolks.
Here’s a look at the key predators that impact waterfowl production.
Red Foxes Red foxes are a primary predator limiting duck production in the prairie pothole region, particularly for upland-nesting species such as mallards and pintails. Why? For one thing, research suggests they specifically seek out duck nests, rather than finding them opportunistically like most other mammals. They also want more than just eggs — they creep in stealthily in hopes of pouncing on the hen, which of course leaves no chance for renesting. Foxes frequently cache newfound eggs — that is, squirrel them away for later — and move on to the next nest.
Raccoons Raccoons generally don’t actively target duck nests, but they’re happy to eat most or all of a clutch when they happen upon one. And happen upon them they do, in their travels along prairie wetland edges, farmland ditches and other places breeding ducks nest. They’ll eat ducklings, too, although their consumption of eggs is far more detrimental to the fall flight. Notably, raccoons are not native to all of the prairie pothole region, and ducks didn’t have to contend with them in prairie Canada until about the 1950s.
Skunks Like raccoons, skunks are foraging animals that delight in chance encounters with duck nests and occasionally eat ducklings, too. Research funded in part by Delta Waterfowl suggests that the average skunk depredates at least two or three duck nests each spring — which adds up quickly in regions with high skunk densities — and that skunks feed most heavily on duck eggs in early spring when food alternatives are scarce.
Coyotes Many assume that coyotes are public enemy No. 1 for nesting ducks, given their size and abundance. While they will eat ducklings, scavenge eggs and kill any hens they manage to catch, they also drive away foxes and other preeminent breeding duck predators. Thus, while coyotes have a net negative impact on breeding ducks, the losses are somewhat offset by the coyotes’ displacement of more aggressive nest raiders.
USFWS National Digital Library
Badgers Badgers are a major duck-egg predator across much of the prairie pothole region. In a 1999 study published by Notre Dame and conducted in west-central Minnesota and southeastern North Dakota, waterfowl flesh was found in the stomach contents of 32 percent of the badgers sampled, while 27 percent contained ducklings, and a whopping 60 percent had recently consumed duck eggs.
Mink These fanciful, semi-aquatic mammals are occasional egg-eaters and kill a lot of ducklings in the prairie pothole region. In dry years, when wetlands retract from the surrounding vegetation and ducklings are left exposed, mink can exact an especially grave toll on how many survive to migration. Otters, a relative of mink, similarly affect duck production in areas such as Nova Scotia, where their numbers are increasing.
Corvids The corvid family, which includes crows, ravens and magpies, poses a formidable aerial danger to waterfowl eggs and ducklings. These birds are more plentiful in the parkland habitats of central Alberta, Saskatchewan and Manitoba — which have ample trees and therefore support high corvid populations — than in the prairies of the Dakotas and southern Canada. And because the Canadian parklands are a critical region for over-water nesters such as canvasbacks, redheads and ring-necked ducks, corvids strongly affect these key diver species. Crows used to be considered the top avian predator for waterfowl, but recent data suggests that ravens are far more destructive and their numbers have dramatically increased in parkland habitats that support canvasbacks.
Gulls One might think the secluded breeding habitats of eiders and other island-nesting sea ducks would be relatively protected from egg-eaters. However, a recent influx of gulls and other predators is significantly limiting nest success and duckling survival in coastal Maine and Canada’s maritime provinces. Predation by black-backed gulls, in particular, is believed to be a leading cause behind declines of common eider populations in the Atlantic Flyway. The gulls perch in wait, and strike when hens leave their nests unattended.
Other Nest Predators The list goes on. Despite steep population declines, Franklin’s ground squirrels remain a significant nest invader in key portions of the prairies. Birds of prey, including hawks and owls, eat eggs and ducklings, and the recovery of bald eagles in the East is thought to be putting a serious dent in eider duckling survival. Snakes are well documented wood-duck nest raiders, while snapping turtles, largemouth bass, northern pike and even bullfrogs pull plenty of ducklings below the surface. Feral cats, weasels, opossums and herons are also on the hunt for newborn ducks.
To be certain, a juvenile duck that finds itself winging south with winter’s chill at its back has overcome all manner of odds. — Kyle Wintersteen