Geese and Mussels

The sound of Canada Geese is one of my favourite signs of spring – “goose music”, as Aldo Leopold called it. Their northerly migration is also marked by the return of feeding signs in PEI’s bays and estuaries, and some related behaviour that may surprise you!

You may think of Canada Geese as herbivores that feed on aquatic vegetation and grasses in spring and summer, and the remnants of agricultural crops in fall. But, like many herbivores, Canada Geese are not strict vegetarians and will eat meat when the opportunity arises. And, during the spring migration, shellfish present an irresistible opportunity!

If you’ve walked the shores of our Island’s bays, estuaries, or tidal rivers lately you may have noticed lots of crater-like depressions (main photo). Your first thought might be that these were human-made, but that’s not the case: this is the work of Canada Geese. The retreating tide reveals the depressions, but they were made under shallow water. The Geese float in the water above the sediment and paddle their feet to stir up the mud. This creates these distinctive bowls, and uncovers the tasty shellfish within them.

Further evidence of this mussel-munching habit can be found in the scat. Canada Goose scat is usually the firm, cigar-like tube typical of herbivores (upper right photo).  But when they’re feeding on protein-rich shellfish, it’s much softer and more like what you’d see from carnivores and scavengers (think Herons or Gulls). In the lower right photo, you can clearly see the remains of Blue Mussel shells, ground up by the goose’s muscular gizzard and excreted (conveniently on top of some intact Blue Mussels).

If you’re exploring our Island’s coastal waterways this spring, keep your eyes open for signs of Canada Geese, Blue Mussels, and other members of PEI Untamed!