Article by Sian E. Ford
As summer reaches its peak and the colorful migrants of Spring disperse, other less amiable birds can come into focus. I began bird watching and banding during my undergraduate studies in university and all I had ever heard of the northern goshawk was that they are rarely seen but are highly aggressive to the point of dispatching neighboring raptors viewed as a threat. The Latin name for this bird is Accipiter gentilis which is “gentle/noble hawk” which, while derived from their restricted use by the nobility for falconry in the Middle Ages, is an interesting choice given this infamous behavior.
My first encounter with northern goshawks came in Alberta during the summer of 2017 after my parents excitedly informed me that they had seen a pair in their yard collecting nesting materials. It was only a few weeks later when my parents came to realize their new raptor friends were also responsible for the decrease in visitors to their bird feeders. Late that summer I set out with my dad into the forest behind their countryside home in search of nest site. My dad had a rough idea of where it might be as he had tried to follow the parents previously but to no avail, so we set out in the early morning in muck boots, with our binoculars and high hopes. Once in the region where my dad had seen them before it took no more than two minutes before the birds appeared and we quickly learnt that their aggression had not been understated. In perfect silence, the much larger female dove at me in a warning pass barely a foot from the top of my head. The male soon followed and the two began calling in a frenzy, attempting to lure us in the opposite direction. I was astounded that both birds had remained completely undetected by me until they were directly overhead or had passed by me. Not wanting to further disturb their nest site or breeding we took the hint and hiked back out with both birds taking the occasional dive during our retreat.
Northern goshawks owe their maneuverability to their short, broad wings and long tail which allow them to hunt in their forest habitat. Their hunting strategy involves the silent stalking of prey preferring to strike undetected, but will pursue fleeing quarry at high speeds, recklessly diving through underbrush and even into water to catch a meal. A hunt may even conclude on foot! Northern goshawks have been observed chasing prey into denser brambles, running with a hurried, crow-like gait. Prey will include any mammal or bird it can catch and subdue sometimes more than twice the size of a northern goshawk, including other birds of prey such as osprey and great-horned owls.
Their circumpolar distribution gives them a total range of 30 000 00 km2 but their secretive nature makes it difficult to determine total numbers. Their elusive nature increased during incubation, where females will become quieter as they tend to a clutch of 2-4 eggs. Hatching occurs after approximately 30 days with fledging six to seven weeks after. During the sixth week, young northern goshawks become “branchers” as they leave the nest to sit in nearby branches. At this stage they begin practicing basic hunting skills by grasping and striking at branches and perches, often tearing away leaves and tossing them up and over their backs in a very comical gesture. By 3 months of age the young are fully independent of their parents.
Should a northern goshawk make it through their second year, the average lifespan in the wild is up to 11 years on average. However, deforestation of old-growth forests continues to threaten nesting habitat globally. Due to their preference for dense canopy cover, timber harvesting methods that reduce this cover are the most detrimental. In Europe and Asia northern goshawks seem more resilient to loss of dense canopy forest, but this adaptability is not universal and long-term regional declines are seen in Canada and the American southwest. Conservation and ecologically conscious harvesting of old growth forests is vital to the continuation of this incredible and powerful bird.