The Conservation Issue

The Northern Spotted Owl is listed as a threatened species by The Endangered Species Act.  There is estimated to be between 2500 and 5000 breeding pairs left in the world (Natural History 2014).  The primary reason for this has been the logging of their habitat, old growth forests, and habitat fragmentation (All About Birds 2014).  With this being the case the introduction of an invasive species into their diminished habitat is a serious threat to the Spotted Owl's survival.  The issue with the Barred Owl is it's generalist nature.  The Spotted Owl is considered a specialist, because it requires specific habitat and prey to survive, and does not adjust well or at all to change  (Natural History 2014).  They rely on Old growth forests for cover while hunting and tree hollows for nesting. They also require large home ranges.

Northern Spotted Owl in flight

Northern Spotted Owl Chicks

The Barred Owl is considered a generalist.  It can live in a variety of habitats, including urban ones.  It is a ground forager so it requires less forested areas to hunt, and it will nest in hollows like the Spotted Owl (Barred Owls 2014).  These owls require a small range and can rely on many prey items for food.

Barred Owl with prey

Barred Owl in water


With development and urbanization, we have opened up corridors for the Barred Owl to expand it's range (Hamer 2007).  These generalists can adapt to new habitats as they expand their range.  With this being the case, the Barred Owl has started to move into habitat that has traditionally been available for the Spotted Owl.
Their generalist nature allows them to thrive and their small ranges mean more can pack in and negatively affect the Spotted Owl that requires a large range to hunt and nest.  As the Barred Owl population rises in Spotted Owl habitat, we will see Spotted Owl numbers drop as they are out competed for resources.  Even having Barred Owls calling in the area has proven to alter Spotted Owl behavior in a negative way (Crozier 2006).  The question becomes what can we do?  The two cannot both thrive with the other species present. So we are forced with the dilemma of losing one or removing the other.