The fragility of nesting birds and the advent of anti-coagulant rodenticide
I write with a heavy heart that a family of Great-Horned owls that had set up a nest in a suburban neighborhood has been lethally poisoned. We now know that 3 of the 4 members of this family has died of an anti-coagulant rodenticide and we have no idea if the remaining owl has survived. A few days before we learned that 2 owls died and the discovery of the 3rd was today. My hopes dissolved as we tried to find the surviving members without much success. We called to them, but met with radio silence. The culprit: Secondary poisoning of SGAR (Second-generation anticoagulant rodenticides) by feeding on mice and rats filled with poison and dying a slow and painful death.
I have spent over 6 years observing and photographing birds including a couple of local American Bald Eagles. I was thrilled to see baby heads poking of of nests last year, hoping that they will grow to be strong adults. It’s amazing how much resilience they have with the weather, city noise and other raptors that can strike at any moment.
But with the joy, sadness crashes the party with the news that one of the two eaglets is the ground, unable to fly, listless and in critical need of medical attention. The desperate race against time to save the bird from bleeding out has become headline news throughout the birding community. Vitamin K immediately administered to help the blood to clot, fluids and keeping the bird calm enough to do this is a heartbreaking task, to no avail. Eagles have no real facial expressions, but seeing the bird struggle to breath is gut-wrenching. Then the news broke that the surviving eaglet was also showing signs of toxicity and dehydration. Fish laden with Vitamin K was left on the ground, which the eaglet came down to eat. Thankfully, it did survive and managed to fly to Delaware. But because of human intervention, it was hit by a car and died. Both parents have survived this ordeal. As I write this, the two eaglets born earlier this year have recently been fed rats, as the herring for some reason is not been as plentiful as in years past and the parents are not finding success in fishing; a main staple for eagles. I can only hope that they are not victims of poison.
This scene is what has happened far too many times with the introduction of this type of rodenticide. The Covid-19 pandemic has caused much of the rat and mouse populations to scatter outside their usual territory and like any other living thing, must do what it needs to survive. What they don’t have is the human food waste to feast on from restaurants that have shuttered due to Covid. So with that, rats are forced to go further afield to residential homes. Humans have this unholy distaste for any type of rodent running around. Scenes in movies show hoards of rats running in the sewers, disgusting varmin that carry a myriad of diseases. So yeah, it’s going to get people to immediately find a remedy to kill them. But, unfortunately, it also kills anything that eats the mouse or the rat: raptors, dogs, cats, mountain lions, coyote, fox, wolves, carrion birds, etc.
It’s so very sad and very frustrating to have time with them while the are still alive to document the offspring, with fingers crossed that they grow strong and learn how to hunt, only to find out that such a vibrant life was immediately extinguished by SGARs. We are no longer left with confident hopes that raptors we’ve grown to loved will continue to thrive, and that any moment now, another soul will succumb to this horrible poisoning.