A Difficult Identification of a Winter Hawk - Let's Learn

 

                                               What Is This Hawk?  [B Schneider Photo]

                                           Another View of the Same Hawk  [B Schneider Photo]

On December 31, 2022 in the afternoon we saw a hawk near route 105 in the Keswick area, York County, which was being harassed by crows.  It was perched about 4 metres off the ground in a maple tree and was intent on what the crows were doing.  That gave me an opportunity to photograph from the car.  Assuming that it was a lighter coloured juvenile Red-tailed Hawk, we drove on to check other birding areas.  When I downloaded my photos later that day I knew this was possibly something else.  It did not look like a Red-tail, so what was it?  I knew some Red-shouldered Hawks had been reported from the province and was not totally sure what a juvenile Red-shouldered looked like.  It certainly looked like a buteo and I ruled out a juvenile Broad-winged because we 'don't have them in winter'.   At least, that is what we birders have thought for many years.  It looked like a smallish buteo but I had nothing to compare it with so wasn't totally sure of its size.

I returned to the area and could not refind the bird.  I sent the photos to my local birding friend and he thought it was a Red-tail but noted the lighter head.  The next level of help came from another of our well-seasoned birders.  He was unsure but ruled out Rough-legged and was hoping for more photos which would show more of an open wing.  He was asking also if I could give an accurate estimate of size.  Both of these were difficult.  No more photos were available.   He was seriously wondering about juvenile Broad-winged Hawk. 

What to do?  I really wanted to know what this hawk was.  I felt an accurate identification was important for our NB records.  So, I moved to another level of expertise in our province.  All the input we could get was valuable.  After studying the photos carefully he ruled out Red-tailed and Rough-legged immediately and leaned toward juvenile Red-shouldered Hawk.  His reasons seemed valid.  First, it looks similar to the immature Red-shouldered Hawk that was in Saint John in the winter of 2019, noting also that the markings on first-winter Red-shouldered Hawks can vary considerably.  Second, referring to Richard Crossley's,  Crossley's Guide to Eastern Birds, it notes that the juvenile Red-shouldered is very similar to the juvenile Broad-winged and it often has evenly spaced heart-shaped streaks.  Crossley also says that the Red-shouldered juvenile has pale areas above and below the eye.  Both these features are seen on the bird we are trying to identify.  However, since the identification is still uncertain, it was suggested I seek the help of our chief hawk birder, Todd Watts.  

The plot gets deeper and more interesting!  So, we have the possibility of either a juvenile Red-shouldered or a juvenile Broad-winged.  After close examination of the photos and referring to many hawk identification texts  (and many hours of hawk identification experience) Todd points out the following for our consideration.  Referring to the photos of our mystery bird, note the lightly marked underside of this individual.  The barring and streaking is mostly limited to the flanks.  This is typical of immature Broad-winged and uncommon in Red-shouldered.  The heart-shaped markings occur on both Red-shouldered and Broad-winged  but they are evenly spaced on the Red-shouldered juveniles which they are not on our mystery bird. 

Todd searched dozens of photos from the Macaulay Library, Cornell Lab or Ornithology,  and submits two as shown below.

                    Juvenile Light Morph Broad-winged Hawk [Macaulay Library]

                        Juvenile Light Morph Broad-winged Hawk [Macaulay Library]

According to Todd, our mystery bird shows many similarities to the above photos of juvenile Broad-winged Hawks.  The heart-shaped spots (although not really diagnostic) are not evenly spaced.  Also similar to the photos are the distribution of the underbody markings, the head markings and the general colouration.  One of the Macaulay photos shows a pale forehead and the other does not.  A pale forehead is common in juvenile Broad-wings but not always present as in the second photo above and in our mystery bird.  Todd notes a mid-throat streak on our bird which is not shown in either of the Macaulay photos.  However, mid-throat streaks occur regularly in Broad-winged Hawks.  

Todd concludes that the mystery bird is a juvenile Broad-winged Hawk.  He sent my photos to one of his hawk identification teachers and his reply was affirming; "In my opinion this is unequivocally a hatch-year Broad-winged Hawk".

So, Broad-winged Hawks here in winter?  In local parlance, who knew?  This certainly was my first thought and I have been birding for many years.  According to our NB Winter Bird List kept by Gilles Belliveau, we have had confirmed Broad-winged Hawk sightings in winter for the last 5 out of 6 years.  And these were juveniles! So what is going on?  This appears to be a recent phenomenon of which many of us are not aware (including me).

What we do know is that juvenile Broad-winged Hawks are very intimidated by the crossing of large bodies of water.  We also know that large flocks are seen circling around southwestern Nova Scotia in the fall.  One might assume this is because they are afraid to cross the Gulf of Maine into southern Maine.  By the end of September and early October most of the adult Broad-winged Hawks in their migration have reached Texas.  What is happening to these flocks of juveniles?  Are the juveniles that we are seeing here in winter stragglers from these flocks that can't seem to find their way south?  

The final destination of these flocks of juvenile Broad-wings is a mystery.  According to Todd, they are rarely seen at New England hawk watch sites.  Are these Nova Scotia flocks breaking up with some managing to make it back to New Brunswick?  How well will they winter?  Todd believes that most of them will not overwinter because of their wasting of fat stores trying to find their way.  Adding to that the tough conditions that winter presents and I expect very few over-wintering juvenile Broad-winged Hawks make it into spring.  Broad-wings are not accustomed to our winters!

This has been a fascinating exercise in hawk identification.  Thanks you to the birders which offered help.  In addition to what I learned about juvenile buteos, I learned that things are changing here for overwintering hawks.  Birding can become complex at times and collaboration often solves difficult identification problems.