One of the best things about participating in Arlington Regional Master Naturalists is getting to meet some really wonderful people - fellow nature nerds. One of my classmates, Kelly Geer, a former Wildlife Biologist and all around cool person, was kind enough to share this footage above with me for use on this blog. (Thank you Kelly!)
Kelly first noticed the fish in the water that seemed to be swimming strangely, on its side. Then upon closer inspection, she realized it was actually dead and floating, with turtles nibbling on it from below, pushing it forward. Then, the Great Blue Heron (GBH) (the largest heron in North America), stole the fish from the turtles and attempted to eat it. While GBHs prefer live prey, they are not above opportunistic scavenging. As seen in the video above, the GBH attempts to swallow the fish, but has trouble because of its size. It appears to be dunking the fish into the water in an attempt to lubricate or reposition it. The heron is smart to be cautious, as choking to death is a real danger for this bird. It's long slender neck, which gives it the powerful spear hunting method, also makes it difficult to swallow bigger prey and its possible the food can get stuck, killing both animals.
Suddenly, a bald eagle swoops in.
While the Bald Eagle has an excellent marketing team, the truth is that these birds often steal food from smaller birds, so it may have been trying to steal the fish. However, some sources suggest that Bald Eagles are occasional predators of adult Great Blue Herons - so that could also be what is going on. Based on the dramatic expression and quick exit made by the GBH, it seems the heron did not want to stick around to find out if the eagle wanted his meal or to make him a meal. The eagle doesn't try to find the dropped fish and seems to fly off after the heron.
And then, Kelly told me with a smile, the turtles resumed munching. It sounds like a fable: The Turtles, the Heron & the Eagle - in which the turtles, despite their speed and size, are ultimately victorious in the battle for lunch.
---
Great Blue Herons are beautiful, fascinating birds. At 4.5 feet tall, they are taller than some children, but they weigh only about 5lbs (about the same weight as a pack of printer paper) because their bones, like most birds, are extremely lightweight. While flying they actually have a 6-foot wingspan! This photo of a young GBH looks like a dinosaur because, well, birds are dinosaurs. Paleontologists are agreed that modern birds are descendents of theropod dinosaurs. More on this exciting topic here and I would encourage you to share this fact with a small child that loves dinosaurs.
This drawing of the skeleton of a Great Blue Heron in an old book, titled Osteologia Avium, depicts the impressive adaptations this species has made to survive. Here is a real skeleton, for reference, from the New York State Museum.
That wild s-shaped neck evolved so they could pack a powerful and fast punch when spearing fish while they stand silently above in shallow waters. Macken Murphy talks more about how the GBH hunts in his Species Podcast episode on Great Blue Herons. The Great Blue Heron's famous colors help them blend in with the grey/blue sky above. All About Birds, a fantastic resource on birds by the Cornell School of Ornithology, lists the food on their menu as such:
"fish, amphibians, reptiles, small mammals, insects, and other birds. They grab smaller prey in their strong mandibles or use their dagger-like bills to impale larger fish, often shaking them to break or relax the sharp spines before gulping them down."
Another cool fact about Great Blue Herons is that, while they are solo hunters, they are actually social animals and nest in groups, sometimes just a few pairs but often larger groups with dozens of couples. Both male and female take turns incubating the eggs. The young can typically fledge about two months after hatching, but the parents continue to feed the young birds for a few additional weeks.
This week in ARMN we are studying Ornithology - including how to bird by ear, why birds are so important (hint: many reasons), what we can do to help protect Eastern Bluebirds from its arch nemesis - the common and invasive house sparrow (aka HOSP to people in the know), and how caterpillars are a crucial food source for many types of baby birds because of their high levels of carotenoids.
Fun fact: It takes between 6,000 and 9,000 caterpillars to raise one brood of 3 Carolina Chickadees. Source: Nature's Best Hope by Doug Tallamy
Pro tip: Oak trees host the most number of caterpillar species of any tree, 557! So if you are going to plant a tree, plant an oak. If you love birds, you can help them by planting natives, or at least not planting invasive plants that take up resources, crowd out natives and don't even contribute to the energy cycle. To find out what other plants you should put in your yard to help raise the thousands of caterpillars needed by local bird families - use the Native Plant Finder tool.
Sources:
https://www.livescience.com/are-birds-dinosaurs.html
https://en.wikipedia.org/wiki/Theropoda
https://www.allaboutbirds.org/guide/Great_Blue_Heron/lifehistory
Nature's Best Hope by Doug Tallamy
https://www.nwf.org/Educational-Resources/Wildlife-Guide/Birds/Bald-Eagle
https://www.spokesman.com/stories/2010/mar/28/eagles-find-herons-easy-prey/
http://naturemappingfoundation.org/natmap/facts/great_blue_heron_k6.html
https://open.spotify.com/episode/6ntSNG1xvuVx2qOJ0hK1HD
No comments:
Post a Comment