Raptor Battle

I was with a group of birdwatchers who witnessed an intense skirmish between a Northern Harrier and a Red-tailed Hawk recently. The action lasted for more than 30 minutes as the harrier harassed the hawk while leaving the scene periodically and returning to continue the battle. It was a battle of agility versus size. It was unlikely that either bird would get seriously injured unless the smaller harrier got close enough for the hawk to grab it. Its goal was to harass the hawk until it got tired of it and moved on.

In one corner, weighing in at 11-27 oz. (300-750g), was the slim and agile Northern Harrier.

And in the other corner, weighing 24-46 oz. (690-1300g), was the heavyweight Red-tailed Hawk.

At first, the harrier was circling and swooping at the hawk while it was in a tree. The harrier flew off for a while and the hawk went down to the marsh. Then the battle was renewed as the harrier returned. These are some photos of the ensuing kerfuffle.

The hawk returned to the trees but the harrier would not give up and kept returning until the hawk eventually left the area.

Why did the Northern Harrier attack the Red-tail so vigorously? Birds will often defend nesting sites against larger birds. But harrier breeding season doesn’t start until March. Also, while harriers do breed here occasionally, it isn’t common. So protecting a nest site is off the table. The best explanation seems to be that the Northern Harrier, a raptor known to be very aggressive about keeping other predators out of their preferred hunting grounds, simply wanted the hawk to leave the marsh. Whatever the reason, this harrier was not taking no for answer when asking the hawk to move on.