Grouse on the rise: State bird's population showing improvement after devastation of West Nile virus

Nov. 24—Pennsylvania's state bird population is on an upward trend despite years of decline from West Nile virus.

According to Lisa Williams, the Pennsylvania Game Commission's division chief of wildlife diversity and former state ruffed grouse biologist, the combination of shortened hunting seasons and aggressive habitat work have helped boost grouse numbers.

"The best we can say is that the population is spotty," Williams said, "but generally the hunters that I'm hearing from are pretty happy — pretty optimistic."

The year 2018 was deadly for grouse due to virus-carrying mosquitoes. But flush rates reported by hunters rose 20% in 2019, and another 10% in 2020.

"Grouse are productive," Williams said. "They still put a bunch of eggs in the nest and they still get a lot of chicks on the ground, so they're doing their part. And that's why we keep talking about how we can put the odds back in the favor of those birds."

She added: "We can't directly influence their production, but are there other things that we can do to really help and enhance that production?"

Williams said grouse numbers will likely never be as high as they were in the 1950s, '70s, and '90s — "when grouse were sort of everywhere" — but she remains positive.

"I think it's going to continue to be spotty, but we see the upward trajectory," she said. "Things are improving. That's our best hope. We can't do anything about West Nile virus. It's here to stay.

"How can we get the production up on these birds and give them the extra time they need for them to adapt to West Nile virus, if they're going to?"

In her new role, Williams now oversees non-game birds as well, but admits she has always maintained that properly managing grouse was never about that single species.

"If we get this right for grouse, we're benefiting other young forest species," including those impacted by West Nile virus.

The Pennsylvania Game Commission (PGC) is currently interviewing candidates to replace her as the grouse biologist. She hopes to work closely with her successor and continue to strengthen that message.

Impact of weather patterns

All birds species are suffering from warmer weather trends, Williams said. For grouse, earlier springs and later autumns mean more mosquitoes that bite tender eye linings and probe between leg scales.

"In the spring, you almost don't know what to wish for because for chicks, in June, and even for hens incubating in May, you're really kind of wishing for warmer weather," she said, "but that speeds up the rate of West Nile virus infection. So if you're talking about mosquitoes and disease, you're really kind of wishing for colder weather.

"That early spring temperature — March, April and May — really kind of sets the stage for the rest of the year in terms of disease."

Williams said that if hadn't have been for this year's cold spring it would have been a bad year with the virus, as the summer was rather wet.

"If we would have also had a warm spring, everything would have been in the favor of the mosquitoes," she said.

The virus varies every year.

"It depends on every month of the spring and summer that's tweaking it to the benefit of the disease or to the detriment of the disease — temperature, rainfall — so it's tough."

Ironically, cold spring weather can be just as detrimental for grouse chicks, especially during the first two weeks of life. Mother hens brood them up under their feathers, so the chicks can survive the cold, but since insects are their primary source of protein, the lack of food can lead to starvation.

"It's that insect activity that really causes the issue when we talk about a cold spring," Williams said. "It's more important than the chicks being warm or not."

Habitat enhancement

Only the strong survive.

"If they're not getting the fuel they need, especially if they're a weaker chick, they can pretty quickly start to slide," Williams said.

She pays particular attention to the weather during the first three weeks of June, when grouse chicks are in their infancy.

"Insects during the day are really critical, because they need that high, high protein diet to grow — for muscles, bones and feathers," she said.

PGC land managers have been creating grouse habitat on state game lands with such tactics as prescribed fires to burn off invasive and undesirable plant species that rob the forest floor of sunlight. The practice adds ash that promotes new growth.

"It's a good way to prep a stand for eventual over-story removal, which is what we want for grouse," Williams said. "Any management that gets more sunlight on the ground and gets more native growth going at ground level."

To combat mosquitoes, land managers have also been removing stagnant water, such as shallow puddles, ruts and ditches that serve as mosquito incubation sites. Unlike wetlands, which have established food chains with newts and dragonflies that feed on mosquito larvae, shallow depressions that temporarily gather water, dry, then repeat the process, are a problem, as their temporary nature keeps a food chain from developing, Williams said.

"Those little shallow puddles, because there's no predation, just become mosquito factories," she said.

Promoting habitat improvement on ridge tops and higher elevations instead of wet bottom lands and hollows — where mosquito densities are higher — has yielded better results, Williams said. "If we can put our habitat up there, we've kind of stacked the deck in favor of the birds."

The game commission currently offers a combined eight weeks of grouse hunting with a two-bird-per-day bag limit.

"We know that hunting is not the main driver of what's going here," said Williams, who claimed that less than 4% of grouse hunters hit the bag limit. She said a two-bird limit has more to do with recreation opportunities than damaging the population.

"If you harvest a bird at 10 o'clock the morning on a one-bird bag limit, you're done," she said. "On a two-bird bag limit, you can continue to run the dogs. You can spend the whole day in the woods hoping you're going to get that second bird, but I know you're probably not. So it allows a lot more recreation for individual grouse hunter without impacting the population."

Williams said the two-week, after-Christmas season has remained closed since 2017.

"The big thing we did was shorten the season," she said. "So between that and the habitat management, something in there is making a big difference."

Williams relies on some 950 hunters who faithfully report flush rates and locations to her, which provide her with valuable data.

"These folks have been keeping track of this data since 1965," she said. "We have the best grouse data of any state in the East."

She is grateful that the support of hunters has accelerated her research beyond her expectations.

"This partnership between the grouse program and the game commission and grouse hunters in Pennsylvania has been phenomenal," Williams said. "It's amazing."

Williams is also asking successful hunters to turn in wing, tail and rump feathers from grouse to determine the rate of adult and juvenile harvests. She added that non-hunters can help by simply turning in birds to the game commission — dead or alive, as grouse that may be acting oddly are most likely suffering neurological effects from West Nile virus.

"If you're finding dead birds, even if it seems like they've smacked into something, give it to us," she said. "Because, we started seeing that some of these birds that are smacking into stuff also showed evidence of having West Nile virus."

Live or freshly deceased birds can be turned in for study by contacting a PGC regional office. A wildlife health technician will come for the bird.

"We definitely want to hear about any dead grouse that are found," Williams said, "and if they're in good shape, we'll pick them up."