It was an unusual sight Tuesday in Riverside Park. A group of University at Buffalo students armed with white, mesh butterfly nets fanned out over the Olmsted park in the northwest corner of Buffalo in search of common milkweed.
The unadorned, bushlike plant with the oblong leaves might be considered an unattractive nuisance in most gardens.
However, it is the primary source of sustenance for the monarch butterfly. It was purposely planted in various spots in the park by the Olmsted Parks Conservancy to attract the butterfly.
That makes Riverside Park an ideal place for capturing and tagging the colorfully winged critters before they continue their migration south, said Dr. Nicholas Henshue, a professor in the Department of Environment and Sustainability at UB.
"Geographically, it made a lot of sense that they would be here in the Northtowns, especially here, in Riverside, because of the narrowness of the (Niagara) river," said Henshue.
The monarch butterfly population has been in decline in recent years, so Henshue's students are involved in a project that includes tagging the butterflies. The tagging program is being done in conjunction with "Monarch Watch," which is affiliated with the University of Kansas.
Once caught, before their migration south to Mexico, the monarch butterflies are tagged with tiny, white serialized plastic stickers that are placed on the monarchs' wings – which are recovered from the butterflies once they reach their southern destination.
"These butterflies we're tagging, they're going to, hopefully, be caught in Mexico. They're going to look at it and say, 'where were these tagged from?' And it will be from Buffalo, New York. I'm excited to see how many Buffalo butterflies made it down to Mexico," said Fabio Espinal, a senior from Suffolk County.
Jenna Pecky and Jenna Hoffman, both undergraduate teaching assistants in Henshue's class, said tagging butterflies is a delicate operation.
"You take your index finger and your thumb ... and you pinch the rings together. Then, on their dorsal cell, I think it's called, it's a small white sticker with a number and stick it on their dorsal cell and you pinch that on them very gently, but still, like, firmly. Though, you don't want to break their wings, obviously," said Pecky.
The butterflies are then released.
"So the butterflies that we tagged today probably won't make it back to this specific place, but next year they will migrate back up from Mexico and spend the summer in Canada and then come back down through Riverside Park or Times Beach again in this endless cycle, back and forth from Canada to Mexico," Pecky added.
Hoffman said the project is not specifically designed to save the monarch butterfly, but the students are playing a vital role in that effort by studying them.
"This will help us see how the population is changing constantly and, hopefully, through our efforts we can see the population rise eventually," said Hoffman.
Riverside Park is a preferred resting spot for migrating monarch butterflies.
Not only do the monarch butterflies eat the milkweed plant, but it is also where the females lay their eggs, on the underside of the leaves.
"Each female monarch can lay between – give or take – 750 to 800 eggs in her life. Out of those, maybe two of those are going to make it into adulthood," said Henshue. "All they'll lay their eggs on is milkweed species."
The monarch butterflies also eat nectar from flowers and the leaves and stems of other plants, but milkweed is critical for larvae, which are nourished by the sap in the leaves and stems. The milky, white liquid is a very sticky latex.
"The reason they lay their eggs on these is because the latex is so bad tasting that it will make the butterfly taste terrible (to potential predators). That's why monarchs are inedible," Henshue said.
After gathering under a shelter in the park, Henshue, before issuing instructions, had the students spread out in teams, sending some to the north side of the park near Niagara Street to examine the milkweed there.
In addition to seeking adult butterflies to tag, the students were on the lookout for caterpillars, even those in the pre-caterpillar stages and eggs.
"They've actually stopped laying eggs," Henshue said.
Henshue said he participated in a similar activity several years ago in Cape May, N.J., with the New Jersey Audubon Society, "but then looking at different methods that we could teach to the students."
His students, Henshue explained, are looking at monarch butterflies as an indicator of what is going on in a particular environment, sort of as a proxy for how other pollinators and various invertebrate species and even native plants are being affected by changes in conditions.
"We look at the monarchs not just from a butterfly perspective," he said. "They're charismatic; we're paying attention to them, but what does all this mean for the other stuff that lives here?"
Monarch butterflies are an integral part of the whole ecosystem in which they live.
"Biodiversity is a lot like taking apart an airplane. Now, at first, you might get away with throwing out the pillows and the ashtrays and stuff like that. But, after a while, you're going to get to a species that you actually need to make the plane fly," said Henshue.