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NB Naturalist Feature: Black-capped Chickadees Foraging for Wild Cucumber Seeds

Photo: Jim Goltz

Black-capped Chickadees Foraging for Wild Cucumber Seeds

On the morning of October 20, 2020, Anthony Brooks and I stopped to admire an exceptionally prolific stand of fruiting Wild Cucumbers (Echinocystis lobata) near the start of the Magaguadavic Siding Road just west of Thomaston Corner.  Although Wild Cucumber, like its domestic garden relative, is in the melon (Cucurbitaceae) family and has a viny growth pattern, the resemblance stops there.  The fruits of Wild Cucumber are roughly oval, mostly membranous (rather than succulent), covered in spines, and not edible.  Most of the Wild Cucumber fruits at this roadside location had already split open (=dehisced) along their lower (apical) end and shed their seeds.

| Wild Cucumbers, J. Goltz

As we perused the colony looking for intact fruits to photograph for comparison, we noticed that several Black-capped Chickadees were also taking a keen interest in this stand of Wild Cucumbers.  The chickadees would fly to a fruit and cling upside down to the lower end, effectively scrutinizing each to see if the Wild Cucumber seeds were still present.  If not, then they would quickly move on to check out the next one.  If seeds were still present, then the chickadees would devote themselves to extracting the seeds, one by one, and would fly off to the branch of a tree or shrub to tap open the seed coat and eat the seed contents.  The chickadees were remarkably adept at quickly finding the fruits that still contained seeds, much more so than Anthony and I.

| Wild Cucumber seeds, J. Goltz

You might wonder why I decided that it was worthwhile to share this observation with readers of the NB Naturalist?  Black-capped Chickadee, the provincial bird of New Brunswick, is a ubiquitous, endearing, cheerful, hardy and resourceful bird species that can be found in the province throughout the year.  Wild Cucumber is a native plant that is fairly common and widespread in the province, mainly occurring along the floodplains of lakes, ponds and rivers, and also growing in roadside ditches, and the margins of swamps and other wetlands.

  In the nearly 60 years in which I have been a naturalist, I had never before witnessed chickadees engaging in this behaviour.  I shouldn’t have been surprised since the seeds of Wild Cucumber are black and slightly larger than striped Sunflower seeds, and provide a substantial amount of food for a small bird.  One of the best rewards for being a naturalist is the joy and surprise of encountering something that was completely unexpected.  For most of us, something new can be found on almost every nature foray if we take the time to look.

— James P. Goltz

2021-01-27T15:02:13+00:00