The Connecticut Department of Energy and Environmental Protection (DEEP) is conducting a large-scale assessment of mallards’ nesting success, including brood movement and habitat selection.

The wildlife division is encouraging the public to participate by submitting information about nests they encounter this year and in 2023.

According to the DEEP educational webpage about mallards, “The male or ‘drake’ is recognized by its glossy, green head and white neck-ring. It has a yellow bill, rusty breast, and white tail. The female is mottled brown and has an orange-yellow bill and a whitish tail. Both have orange feet and a blue speculum (patch on their wing) framed with a white bar on each side.”

Migratory Bird Program Leader Min Huang shared that this statewide initiative began due to concerns about the mallard populations declining across the Atlantic seaboard over the last decade.

“Here in our state, we decided that we wanted to look at one critical aspect of any organism’s life cycle, that of reproduction,” he said.

Huang noted that not a lot of studies on mallard nesting has been done in the east. Most research has been conducted in the prairies and western part of North America.

“We developed the study four years ago, but unfortunately COVID put it on the back burner for a couple years,” he said. “We were able to initiate work last year, but this year is really our first real full-on effort. We did get some good data last year, but this year we are really hitting the ground running.”

DEEP is focusing on mallard habitats and what it means for nest success in Connecticut.

“Typically, in the prairies, you see nest success at about 15-20% and that is usually a good number,” Huang said. “We want to know, how is nesting success here? Where are these birds nesting and what types of habitats are lending themselves better towards higher nest success?”

To have nest success, researchers investigate how many of the ducklings survive to fledge and if the area they are in is a factor.

“Fledging is when they are able to fly and where they are basically on their own,” Huang explained.

Typically, the average clutch size for the mallard is about ten eggs.

“Of those ten, by and large 90% usually hatch if the nest is going to be successful. In each nest there might be one infertile egg — sometimes there’s none, sometimes there’s a few,” he said.

The study will also consider brood movement, which is where the mother takes her ducklings after they hatch.

Predators are another factor in this assessment because mallards face many adversaries.

“Over the last 20 to 30 years our state has become much more populated. We’ve got human development punching in all over the place,” Huang said. “Our habitats have become more fragmented and with that fragmentation we’ve seen a huge increase in the median size of mesopredators — raccoons, fox, coyotes — not to mention the bigger predators — bobcats and bears.”

He later added, “Duckling survival is pretty low. It’s tough being a duck.”

However, if DEEP can learn what habitats mallards thrive in or struggle in, they can work to make improvements for the birds’ survival.

“On the properties that we control at DEEP perhaps we can alter some of our management practices to make those areas a little bit more conducive for high success. The more information we can gather, the better we can try, at least, to have a better outcome,” he said.

DEEP is currently following the progress of mallard nests from Greenwich all the way to Woodstock.

The work does not stop there, though. DEEP is “radioing” birds to follow the ducklings after they hatch to see how they are doing.

“We are actually putting GPS radios on some of these hens. The radios upload data from the cellular telephone network, so we don’t need to recapture the birds to get the data. We can look at what the birds are doing basically in real time,” Huang said.

Public Participation

DEEP’s work will continue through August as birds are still renesting and some are trying to nest for the first time.

“Our technicians have been out in marshes where we know birds are nesting at some point and trying to find nests that way. That’s really the more traditional way of trying to find nests,” Huang explained.

Already this year, the public has significantly helped the study by providing a variety of nest locations across the state.

“When you start looking at where these birds are nesting, there is no way we’d ever find them on our own,” Huang said.

Some people have reported finding mallard nests in their backyards, in the woods, by pools or bodies of water, under arborvitaes, by a chimney, and even in parking lots.

“Mallards will basically nest anywhere, we are finding. The public really has been a great help to us in identifying nests and letting us know, so we can then come follow up,” he said.

Those who come across a mallard nest can e-mail Huang at min.huang@ct.gov with the subject line clearly stating, “Mallard Nest.”

Huang anticipates that data will be released to the public throughout the study, including updates later this year and next year.

To learn more about mallards, visit portal.ct.gov/DEEP/Wildlife/Fact-Sheets/Mallard.

Reporter Alissa Silber can be reached at alissa@thebee.com.