N.B. naturalists optimistic about increase in monarch butterfly numbers

Monarch butterflies worried naturalists last year with a shockingly low presence in the province, but a team of butterfly taggers say this year the species is showing signs of recovery.

Members of the Saint John Naturalists Club headto Point Lepreau each September to tag thebutterflies in the hopeof tracking their migration journey to Mexico and monitoring their health and population.

Birder and naturalist Jim Wilson said in the first week of tagging, the club tagged 136, a jump up fromlast year, when 97 were tagged in total.

"There are certainly more monarchs this year than last," Wilson told CBC Radio'sShift.

Wilson said he is also hearing of more chrysalisesthat have yet to hatch. "There are still quite a few monarch butterflies to come out to start to migrate."

He said monarchs seem to be setting off later this year than last, "possibly because the butterflies seem to come a bit earlier."

Monarch butterflies always leave Mexico at the same time, and the determining factor for when they arrive to Canada is weather, said Wilson."We had excellent weather this summer, as we all know."

Milkweed is the only plant that monarch caterpillars can consume and lay eggs on, so theplants are also crucial forreproduction.

Wilson believes there were two generations of butterflies produced this year, which would explain why the second generation is late to hatch.

Declining population

While the club is feeling optimistic about monarchsin New Brunswick, Wilson said the overall population of the species has been "grim" for decades, with a 90 per cent decline in the last 30 years.

Tagging efforts are most common in the United States, with the University of Kansas spearheading aprogram that provides tags to naturalists across North America.

Just three years ago, the Saint John Naturalist Club taggedabout 1,000 monarchs with tags provided bythe university.

In 2022, the club lowered numberof tags it received from the program to 500, Wilson said,because tagging a thousandbutterflies is a lot of work,and then 2023 saw a very low monarch presence.

The butterflies gather each year for migration and the population is measured by hectare meaning thearea completely covered by monarchs.

The all-time high was about 18.19 hectares in 1997, according to Monarch Watch website.In more recent years, the average population dropped to 2-3 hectares.

Once caught, the butterflies receive a small tag on the hind wing. Any damage or deformation is recorded after weighing each butterfly and measuring itswing length. And how much does a butterfly weigh? Very little, saWilson.

"It's just a matter of a fraction of a gram."

Each butterfly isput on a little dish and weighed, Wilson said.The weight of the dish is subtracted from the total.

Monarchs are also examined for a protozoan parasite called, Ophryocystis elektroscirrha,that looks like tiny, pepper-like black grains under a microscope.

"We're finding very low incidents of protozoan here on our butterflies, just a few in the 136 that we have tagged for far this year and virtually none last year," said Wilson.

He said these parasites aren't lethal to butterflies or dangerous for humans, but they are thought to weaken the butterfly.

Shift - NB11:55Monarch Migration

Monarch butterflies are on the move and once again volunteers with the Saint John Naturalist Club are tagging them at Point Lepreau. While they've only just begun the work, it's already clear it's a better year for the butterflies than last summer. We speak withJim Wilson.