Cooper's Hawk

Cooper's Hawk Visits 

Cooper's Hawk

This week a Cooper's Hawk visited our yard.  I noticed it early in the morning sleeping in a tree on the river side our our property.  It stayed there for at least a half hour giving us ample time to observe and photograph it.  It was perched very quietly and appeared to be sleeping but with a casual eye for its surroundings.  At one point a Sharp-shinned Hawk came soaring on outspread wings around the house, which it often does checking on the bird activity around the feeders.  When it got fully into the yard, it did a double-take, putting on the brakes and doing a quick floundering turn-around and quickly winged its way back in the direction from which it had come. It clearly looked like it spied the Cooper's Hawk and made a quick decision to disappear.  The Cooper's Hawk remained on its perch in the tree.

How did I know the perched hawk was a Cooper's Hawk?  It was obviously large for an Accipiter.  That would make it either a Cooper's or a female Sharp-shinned.  The Cooper's Hawk is larger than the Sharp-shinned with the female being larger than the male.  That is also true of the Sharp-shinned Hawk.  But what makes it sometimes difficult is that sometimes their sizes are close.  The male Cooper's and the female Sharp-shinned can be nearly the same size.  The hawk showed the rufous horizontal striping on the breast of an adult.  Its tail tip was rounded and not square like that of the Sharp-shinned Hawk.  It showed a contrast between the dark cap and the gray nape which is also a trait of the Cooper's Hawk.  And, the behaviour of the Sharp-shinned was also a clue.  It recognized the Cooper's as a threat.  The Sharp-shinned showed its square tail clearly when it did its turn-around.

Cooper's Hawk

For good information on distinguishing a Cooper's Hawk from a Sharp-shinned Hawk, see a previous post on this blog entitled, 'Sharp-shinned or Cooper's?'.  Following is additional information on distinguishing the two species.  The length of the wing tips in the perched bird is a good marker.  In the Cooper's Hawk the wing tips extend less than half way down the tail.  In the Sharp-shinned they extend about half-way down the tail.  Head shape is also significant.  The Sharp-shinned head profile is always rounded.  The Cooper's looks rounded when its hackles are down but it often elevates its hackles.  The Sharp-shinned never raises its hackles.

When the birds are in fresh plumage as in the spring, the Cooper's has a wide white terminal tail band.  In the Sharp-shinned it is narrow.  Although this is not definitive and it is mentioned only in some texts, the distance the striping on the breast comes down may be significant.  In the Cooper's sometimes the striping is only on the breast and does not go all the way to the feet as seen in the photo above.  In the Sharp-shinned it usually comes all the way down to the feet.  Taken alone this is not significant but when taken into consideration with all the other features it may be helpful.  In the bird seen this week and shown above, the tail shape and the crown 'cap' confirmed for me it was a Cooper's Hawk.

This species is listed as rare in this province by the 'Birds of New Brunswick:  An Annotated List'.  It has bred here and is now seen occasionally in winter.  It frequents bird feeders and other areas where birds gather.  It is capable of taking a mourning dove or a robin.  Sharp-shinned Hawks normally take smaller birds.  Peterson's Field Guide to 'Hawks' lists the Cooper's as a permanent resident in Nova Scotia and the very southern part of New Brunswick.  I believe this to be true given the number of sightings we record of this species throughout the year especially here in southern NB.