Egg Hunts in Stanley ParkApril 26th, 2017
If you had your fill of chocolate Easter eggs this past April, Stanley Park offers something a little different: jellied eggs by the hundreds!
The design of an Easter egg is based on a hen’s egg, which like all birds’ eggs has a hard shell, but in the wet areas of the Park you’ll find eggs that look completely different. It’s breeding season for many amphibians and they lay their eggs in the water or in damp sites on land depending on the species. A protective layer of jelly rather than a hard calcareous covering keeps the contents moist. Pond-breeding salamanders like the Northwestern salamanders lay up to 270 eggs in a cluster the size of a grapefruit. Long-toed salamanders, another Park species, lay fewer eggs either singly or in a small mass the size of a plum. People sometimes call all these egg clusters ‘frog spawn’ but in the Park they’re just as likely to be ‘salamander spawn’. Ensatina salamanders breed on land under logs or other cover and the female stays with her eggs; these salamanders have no larval stage before they become adults.
Once frog or pond-breeding salamander eggs hatch, the young tadpoles or larvae will live entirely in the water, and although they’re only babies they are actually predators of many aquatic insects. It can take a surprisingly long time for the young frog or salamander to reach their adult form whereupon they split their time between land and water. In the Northwestern salamander this transformation takes one to two years, in the chorus frog only two months.
Both salamanders and frogs are good indicator species of the health of the Park’s wetlands, so we run regular amphibian surveys. In April, SPES staff and volunteers spent three days at several sites, including Lost Lagoon and Beaver Lake. In their funnel traps they found green frog tadpoles and the larvae of the Northwestern salamander. There were also a large number of Northwestern salamander eggs – over 130 egg masses in two ponds! However, in one of these ponds close to the miniature train, the surveyors found something a little more unusual: the eggs of the long toed salamander. This striking black and yellow salamander is not rare in BC, but it is not commonly found in the Park so the monitors were particularly excited to find evidence of it breeding here.
They were also pleased, and a little surprised, to find Northwestern salamander egg masses and an adult for the first time in Lost Lagoon, specifically in the manmade biofiltration pond at the northeastern edge of the Lagoon. This may be a sign that the water there is cleaner that it looks and that the habitat is suitable for these amphibians. Over the next few months water quality monitoring and surveying will continue.
Under the surface of the water many animals are also laying eggs as the temperature gets warmer. Water beetles and water boatmen lay clumps of eggs on rocks or leaves, while the three-spined stickleback fish lays up to 300 eggs in a specially dug tunnel nest. Laying so many eggs ensures that a percentage of the hatchlings will make it to adulthood. But even so, breeding success isn’t ensured, so don’t destroy or take amphibian eggs if you find them. These species need our help and that’s one egg hunt best avoided.
By Ben Hill, Communications Volunteer