Archive | May 2022

Emergence of Spring Butterflies and Mustard Whites

Eastern Pine Elfin

Eastern Pine Elfin

So far it’s been a strange spring. It took a long time to warm up to 0°C and then a while longer to warm up to double digits. Early April was cold and very windy; it didn’t get consistently above 10°C until April 21, but even then it was too gusty in the afternoons to go looking for butterflies. My first butterfly of the year was a Mourning Cloak seen on April 5th at the Rideau Trail on Old Richmond Road. It was a beautiful day of 13°C, and I figured I had a good chance of seeing my first butterflies of the year there….though it was a toss-up as to whether it would be a Mourning Cloak or an Eastern Comma, both of which hibernate as adults in woodlots. While I saw a few more Mourning Cloak in mid-April, butterfly season didn’t really start until the second last day of the month.

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Mass Emergence: Spiny Baskettails

Spiny Baskettail emergence

By May 14th Ottawa had seen a string of six days with temperatures above 20°C, with the last three above 30°C. The warmth signaled the beginning of ode season, with my first dragonflies of the season – both Common Green Darners – seen at the Richmond Conservation Area (May 10) and Sarsaparilla Trail (May 11, 2022). Common Green Darners are migrants, however, arriving on the warm winds flowing from further south. The true ode season begins once it is warm enough for local dragonflies and damselflies to emerge from the rivers and wetlands in which their life cycle began. All odonates lay their eggs in water, and it takes time – from a few months to a few years – for the larvae to go through the individual stages of molting until they are large enough to begin the transformation from nymph to adult. When the nymph is ready, it crawls out of the water onto rocks, emergent vegetation, or nearby tree trunks or plant stems, and then bursts out of the larval shell through a hole in its back, using gravity to pull itself free. I have seen various dragonflies in the middle of this process a few times; I had never witnessed the full transformation as it takes a few hours for the dragonfly to become ready for its first flight. However, when I arrived at Mud Lake on a sunny day in mid-May hoping to find some warblers, it was a mass emergence of at least 50 individual dragonflies that engaged my attention, and I was able to observe many individuals at different points of the process.

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