CAPE MAY POINT — Her friends aren’t surprised when Rebecca Zerlin suddenly calls out “Monarch!” when they are driving with her.
She’s trained to spot the migrating butterflies from far away in a moving car.
The 25-year-old Cape May Bird Observatory intern drove slowly around a set 5-mile route from Higbee Beach through Cape May Point, clicking a hand-held counter every time she saw one of the orange-and-black butterflies.
Her total was 38 in 20 minutes.
The 20 mph drive and count is repeated every day at 9 a.m., noon and 3 p.m. from early September to late October and provides data for a census of monarchs passing through Cape May on their fall migration to Mexico.
“You are here on a good day,” said Zerlin, of New Orleans. A wind from the northwest and sunny skies had brought lots of the migrants to the tip of Cape May, where they will put on as much weight as possible sipping nectar from wild sources and garden flowers before making the 17-mile trip across Delaware Bay to Cape Henlopen in Delaware.
The data aren’t in yet, but early anecdotal reports predict a strong showing for the beautiful insects that travel thousands of miles to huddle together in trees on protected mountainous land in the Reserva de la Biosfera Mariposa Monarca, about 62 miles northwest of Mexico City.
The butterflies’ many fans are hoping for a big population rebound this year.
“At the very least, we can say that in Atlantic and Cape May counties lots of people have seen a lot of monarchs in the last generation before migration, which means lots of caterpillars now, and more are going to be headed (south),” said Mark Garland, director of the Monarch Monitoring Project run by CMBO, a part of New Jersey Audubon. “I’m cautiously optimistic.”
The species has declined about 90 percent nationally in the last 20 years, with particularly rough years in 2004 and 2013. Bad weather and dwindling supplies of milkweed for the caterpillars to feed on are generally blamed for the crashing population.
The data collected here, however, have shown ups and downs but, overall, a more stable population, said Garland, probably because milkweed is more plentiful along the East coast than in the Midwest, where changing farming practices have wiped it out.
Monarch Watch, a nonprofit associated with the University of Kansas that studies the butterflies and their migration, predicted a big migration count for Cape May and other areas of the country this year, based on the wintering numbers in Mexico and data from the spring migration north.
“In sum, this looks to be a good year for monarchs — with a stronger migration in most regions and a good prospect that the overwintering population will increase from the 2.91 hectares (7.25 acres) of last year to 4 hectares (10 acres) or better this coming winter,” Monarch Watch Director Chip Taylor wrote in July. He predicted Cape May would have a particularly good count this year.
The 26-year-old monarch census has been going on this year since Sept. 1, said Garland, and the numbers have been steady but not yet spectacular. That may be because the weather hasn’t been great.
“We haven’t had the wind pushing in from the northwest until today,” he said Wednesday. “That’s the sort of wind that fuels migration.”
Winds from the northwest not only help monarchs migrate south but also push them toward the east, where they congregate in Cape May Point. If winds are more from the east, as they were for much of last year’s migration, the monarchs end up passing farther west than Cape May.
Last year’s numbers were the third lowest in the project’s history, with an average of 15 butterflies seen per hour compared to 38 per hour the year before, Garland said then. The high was about 360 an hour in 1999, and the low was 8.9 per hour in 2004 after a bad winter killed off many butterflies in Mexico.
“The next few days will be very telling,” Garland said.
After doing the census drive, Zerlin headed for two private gardens at Cape May Point, where she helped tag more than a dozen monarchs.
“We have tagged about 80 this morning,” said homeowner Pecki Sherman Witonsky, who has lived there about 20 years and has been maintaining a garden full of fall-flowering plants like Joe Pye weed and the monarchs’ larval food plant milkweed. She has helped tag monarchs for several years and wrote a book about the migration called “Monarch X-ING” in 2016.
Witonsky was catching butterflies in a net, then carefully attaching small, round, numbered stickers on their wings with friends Lesley Conley, who travels from her home in West London in the United Kingdom each fall for the monarch migration, and Betty Ross, of Yellow Springs, Ohio, and Cape May Point.
The butterflies are not harmed, and the stickers help researchers understand their migration routes and times, Zerlin said.
The tagging program at Cape May has discovered that monarchs that migrate through here stay east of the Appalachian Mountains until they get to the Gulf Coast, then follow the gulf to Texas and then to Mexico.
Thousands of people visit Cape May each autumn to see the colorful orange and black insects come through in large numbers, contributing to ecotourism.
At Triangle Park later in the day, Zerlin showed visitors Betsi Parker, of Cape May, and Sherrie Sykes, of Secane, Pennsylvania, how she tags the creatures.
Then she sat them on each of their hands so they could release them.
“Adios!” they shouted as the newly tagged creatures flew away. “Safe travels!”