I've seen a gazillion interactions between hawks and crows over the 
decades, and since the crows do it year-round, I suspect 
(anthropomorphism warning!) it's basically entertainment for them.

As Maeve says, you absolutely can tell how serious the interaction is by 
the sound the crows make.  When there's a genuine threat, like when they 
spot an owl tucked up invisibly in the top of a pine (which they really 
fear and hate) or a hawk near a crow nest with eggs or young, or if one 
member of the group got a little too daring and got snagged by the hawk 
for lunch, the intensity of the cawing is much greater and the calls 
more frantic.

I remember once a group of crows very aggressively pursuing a Red-Tail 
around and around for more than an hour in a place where I was birding, 
literally screaming at it nonstop, not diving and ducking and playing 
like they usually do, and a fellow birder who'd seen how this started 
pointed out the fresh remains of a crow on a nearby branch.

Otherwise, I've noticed that with particularly a perched adult hawk 
(mostly Red-Tails), the hawk largely ignores them and the crows 
gradually calm down, appear to get bored, sit around on the nearby 
branches hoping the hawk will do something interesting, and then after a 
while wander off and go do something else.  The immature hawks aren't so 
calm and do react to the crows, and then the fun is really on, 
especially if the hawk takes flight.

Similar thing in the air.  The matures may scream in irritation once or 
twice, but the young hawks often twist and turn and try to grab a crow, 
which the crows usually easily evade. Reminds me of a person being 
pestered by a persistent deer fly.

I don't *think* this has to do much with the age of the crows, but it's 
impossible to tell for sure.  But crows do tend to hang out in family 
groups for much of the year, and I've never seen, for instance, 3 or 4 
go after a hawk while 1 or 2 just sit still and wait.

Sorry for all the anthropomorphism, but it's totally irresistible with 
Corvids.

I've never seen Ravens "play" with hawks like this, has anybody else?

Jane
Shoreham

On 8/6/2016 7:42 AM, Roo Slagle wrote:
> Is it all just practice for later in life?
>
> On Sat, Aug 6, 2016 at 7:35 AM, Maeve Kim <[log in to unmask]> wrote:
>
>> How interesting! Maybe that’s what I observed this morning. It looked like
>> an angry and aggressive encounter to my eyes, but the fact that the crows
>> weren’t making their usual mobbing noises might have been because they
>> weren’t actually upset.
>>
>> Maeve
>>
>> On Aug 6, 2016, at 7:14 AM, Ian A. Worley <[log in to unmask]> wrote:
>>
>>> I have seen on a few occasions a juvenile Cooper's Hawk hanging out with
>> several crows.  Unlike your situation, periodically all would rise up from
>> the tree they were in together, with a noisy clamor, swirling around
>> together, and doing lots of harmless chasing.  Then they'd all return to
>> the tree, take a break, and after several minutes do it all over again.
>>>
>>> Ian
>>>
>>> ---------------------------
>>>
>>>
>>> On 8/6/2016 6:59 AM, Maeve Kim wrote:
>>>> There’s a resident family of crows that visits every morning to see if
>> there’s anything new in the compost bin. I’ve become accustomed to their
>> many calls, but this morning things sounded different: not the loud, angry
>> yells of mobbing crows but short, sharp calls over and over. I looked out
>> the window and saw the five crows and one lighter-colored bird. It was a
>> large Cooper's Hawk (presumably a female) in pitched battle with the crows.
>> The corvids would fly at the raptor, one, two or three of them at once, and
>> every time the hawk wheeled and chased - and then came back to the tree
>> where the battle began. This went on for almost twenty minutes before the
>> hawk took off with all five crows in pursuit. I can still hear them yelling
>> in the distance.
>>>>
>>>> Maeve Kim
>>>> Jericho Center
>>
>