Two great horned owlets are offered a diet of mice while recovering at the von Arx Wildlife Hospital.

Baby owls admitted suffering from secondary rat poison

By Joanna Fitzgerald | Director of the von Arx Wildlife Hospital

Poison bait kills rodents, but can also cause mortality in non-target species of mammals and birds either through primary exposure (eat the poison bait) or secondary exposure (eat a poisoned animal).

A great horned owlet and a white-tailed deer fawn were among the thirty-eight animals admitted to the von Arx Wildlife Hospital at the Conservancy of Southwest Florida this past week. Other admissions include a royal tern, an osprey and a Florida softshell turtle.

The great horned owl was found on the ground alert but too young to be out of the nest. The owlet’s sibling was admitted to the wildlife hospital ten days earlier after it too was found on the ground.

Both owlets were responsive; one had wounds possibly caused by the fall. Most concerning for both owlets was the pale mucous membranes in their mouths which is a sign of anemia often seen in birds suffering from secondary rodenticide (rat) poisoning.

The two owlets were immediately started on daily vitamin K injections. Vitamin K, which is necessary for normal blood clotting, is given by subcutaneous (under the skin) injections, with repeated doses until the blood clotting time returns to normal. The owlets also received electrolytes and Chinese herbal supplements which stop active bleeding. The one owlet’s injuries required a course of antibiotics as well.

Both owlets have responded to treatment and are eating on their own. Currently, they are being housed in a large indoor recovery enclosure, which provides them space to exercise and move about similar to what they would do in the wild. The babies will not be moved to an outdoor recovery enclosure until they no longer require daily vitamin K injections.

Rodent Control

Rodent control is a difficult issue with no quick and easy solutions which has negative ramifications for a myriad of species. Many rat poisons contain anticoagulant compounds that inhibit normal blood clotting resulting in excessive internal bleeding and death.

The poison bait kills rodents but can also cause mortality in non-target species of mammals and birds either through primary exposure (eat the poison bait) or secondary exposure (eat a poisoned animal).

Preventative measures and exclusion are long term solutions to rodent issues that don’t compromise environmental health and deserve consideration as viable options.

Recent Releases — 20 Animals Returned Home

  • 1 eastern screech owl
  • 1 mourning dove
  • 1 Florida softshell turtle
  • 1 ovenbird
  • 1 herring gull
  • 5 brown pelicans
  • 2 red-shouldered hawks
  • 4 eastern cottontails
  • 2 grey squirrels
  • 2 double-crested cormorants

Opportunities to Help

Please visit the Conservancy website at to view all of the amazing volunteer opportunities at the Conservancy of Southwest Florida. Your volunteer time, as well as memberships and donations, are vital in helping us continue our work to protect Southwest Florida’s water, land, wildlife and future.