This past weekend, WildResearch held a Butterfly Monitoring Workshop at the UBC Botanical Garden. The workshop began with an indoor classroom session where participants learned to identify, catch, handle, and monitor butterflies. They also learned the protocols for contributing data to the BC Butterfly Atlas, a citizen science project. I sat in, and gave a brief presentation about gardening to attract butterflies. We then spent the remainder of the day in the Garden to apply what we went over during the classroom portion of the workshop.
While in the Garden, we spotted some cabbage whites and a few swallowtails (my identification skills aren’t quite there with this group, because I can’t tell if today’s photo shows a Canadian or Western swallowtail). Whatever the identity (maybe someone can help?), the swallowtails were gathered in the David C. Lam Asian Garden around this Syringa sweginzowii ‘Superba’, or the Chengtu lilac. The group also released some painted ladies. Unfortunately, we didn’t spot any of the orangetips that were released earlier in the year.
When planting to attract butterflies, their entire life cycle must be considered. Many butterflies lay their eggs on specific host plants for the caterpillars to feed upon. For this reason, having native plants in your garden contributes to providing better habitat for native butterflies. For a local example, satyr commas, red admirals, and Milbert’s tortoisehells rely upon stinging nettle as a larval host.
Adult butterflies, on the other hand, are rarely so picky for food plants, ultimately going for flowers with high nectar content–so non-natives suffice. Adults are attracted to large and showy patches of bright-colored and variously-shaped flowers. Maximum interest is generated when eight or more species are flowering simultaneously in a flower patch 2.3 square meters or more (bigger is generally better for attracting adults). Adult butterflies also prefer to sit while feeding on nectar so having flower species that provide a platform, such as asters, is beneficial.
When gardening for butterflies, it is also critical to provide for their needs beyond food. Providing some water and a little shelter with some shrubs is always a good idea. In addition, butterflies are “cold-blooded”, needing to regulate their temperature using their surroundings. If they are too cold, they won’t fly, so are often found basking in the sunshine. Providing basking spots such as rocks may tempt a butterfly to stick around a little longer. Areas that are a bit muddy for “puddling” also helps. This is when butterflies, often males, seek out wet substrates to gain some extra nutrients such as salts and amino acids. While mating, the males pass on nutrients to the females (called the nuptial gift) for reproductive success. Butterflies may also make use of dung for this purpose. Some butterflies also prefer over-ripe fruit to feed upon–but be careful you don’t attract unwanted critters into your garden! On a final note, it’s best to avoid pesticides.