Despite the heat, this week has been phenomenal for songbird migration at the Lesser Slave Lake Bird Observatory. Each day was busier than the last as thousands of birds flew overhead during our seven hour monitoring period in the morning. In total, we counted nearly 17,000 birds from August 21 to 27. Most of these birds were Myrtle Warblers and small numbers of Cedar Waxwings and other warbler, finch, and flycatcher species. In what would become our third busiest day ever for Myrtle Warbler counts, and the busiest day since 2012, on August 27 we counted over 4,400 Myrtle Warblers.
Common Grackle – 9th banded at the LSLBO
We can see these huge numbers of migrants at the observatory thanks to our strategic location in Lesser Slave Lake Provincial Park. We are within 50 m of the lakeshore and near the base of the Marten Hills. Songbirds will avoid flying over the lake because they are so exposed to predators over water. They also avoid flying over hills due to frequently poor weather conditions. As a result they get funneled right overhead for us to count.
I certainly was not expecting numbers this large this week since typically a hot day at the station is a quiet day both overhead and in the nets. While Myrtle Warblers are a short-distance migrant ‘only’ going as far south as Kansas through to the Yucatan Peninsula in Mexico, other species are going all the way to South America around 7,000 km away. As such, migration is like running a marathon. Birds prefer to do it overnight or on calm, cool mornings choosing more often to rest and forage in the heat.
Compared to our counts of overhead migrants, the mist-nets have been relatively quiet. Even our captures have been mostly Myrtle Warblers, but also included our ninth ever Common Grackle and our fourteenth Pileated Woodpecker. Although both these species are too large to be effectively captured by our nets that specialize in smaller birds (they struggle sometimes with American Robins), we can get lucky and catch larger birds.
Bronwyn banding her first Pileated Woodpecker, and the 14th banded at the LSLBO
Common Grackles are a blackbird species that breed locally in wetlands and can be seen during their fall migrations visiting bird feeders. These are our biggest blackbirds and appear even larger thanks to their long tails that are often held in a wedge-shape in flight. Grackles will range through the south-east United States in winter since they can eat grains and do not depend on having live insect prey to survive.
Pileated Woodpeckers are also the largest of their family. They live here all year but have recently become an honourary migratory bird under the Migratory Birds Convention Act which protects all migratory birds and their nests. As a resident, their inclusion under an act that protects bird species that only live part-time in Canada may seem odd, but several migratory species depend on Pileated Woodpeckers to be successful. These woodpeckers carve large cavities into trees that are then used by other species to nest. No Pileated Woodpeckers would mean no holes for those species, which would jeopardize their populations. Whenever safe to do so, dead trees should be left standing to provide these nesting opportunities for Pileated Woodpeckers, and by extension Saw-whet Owls, Tree Swallows, and even Flying Squirrels.
By Robyn Perkins, LSLBO Bander-in-Charge
