Blackbirds?

[centrarchid]

Crows and ravens are members of the blue jay family of birds. There is nothing magical about crows harassing hawks. However hawks (Especially Chicken Hawks) enjoy nothing more than a nice tender filet of crow. The good news is that when the cards are delt in the hawks favor a murder of crows may well provide an alternative food source for hawks, diminishing the hawk pressure on your chickens.

If you are a crow huger the following video may be hard to watch. None the less it illustrates the true relationship between crows and hawks. The flock of agitated crows eventually decides to move on because I assume that there is nothing to see.

Interesting, but far from a slam dunk for hawk to prevail. Female Cooper's Hawk was almost pushed off crow more than once in video. Wing feathers on bird held down appear to have been damaged prior to encounter with hawk. Same hawk grappling one of my hens or offspring in range of a harem master game cock would very soundly driven off if not injured.

 

[FlyingNunFarm]

In the end I’d rather have members of the corvid family hanging around then hawks. I’m not inviting them to roost with my chickens. I’d rather wild birds don’t come close and bring the possibility of diseases.

If the mobbing of hawks isn’t helpful they would at least be an early warning system.

 

[Lazy Farmer]

I think they mean crows / ravens when they say black birds can keep hawks away. I have seen crows harass hawks approaching the crow's nest during breeding season but have seen black birds go after hawks of any kind with the exception of Red-tailed Hawks trying for nestlings.

Here in our neck of duh woods, Giant Black Birds & Hawks go hand-n-hand. They follow the Hawks for great distances while squawking the whole time. It is fun to watch and also is peace of mind as my flocks are ranging.
The "Crow of a Black Bird", is music to my ears.
Mother Nature's gift to weary Chicken Owners.

 

[llombardo]

I have these guys. They even ate with the smaller birds and squirrels when we had a snow storm. They are great at alerting everyone a hawk is around. If you hear them, you will see a hawk. I have seen them surround a hawk until it left. Interesting creatures.

 

[americanchicks]

I love crows and ravens. They are one of the worlds smartest birds. Now do they keep birds of prey away from your chickens? Well I have lived in our new place, 5 wooded acres, for over a year. I have not lost a single hen to hawks. When I lived in the suburbs however I lost 2 hens to hawks. We do have hawks, I have seen them, but every time I do they are being pestered by ravens. I love to hear the ravens call too, so cool. Now the interesting thing is over the past few weeks or so I have not heard or seen any ravens. I have since had two failed hawk attacks on my flock. So who is to say if ravens and crows keep the hawks away. I however would like them to come back, better safe than sorry.