Crows and Hawks

[TwoCrows]

What kind of crow in the area if not a raven. I have two species, American Crow and Fish Crow, that are relatively easy to tell apart by looks, size, flight and voice. The American Crow does not always look like American Crows in other parts of the country. Would be nice to see a genetics study targeting the American Crow. Some American Crows seem to have a live cycle like I understand ravens to have where adults keep a constant territory / home range while immature birds flock up for first year after leaving natal territory.

Love the pics Just curious is there a difference between crows & ravens, or are they the same? Sorry for my stupid question.

Yes, Ravens differ from Crows in their territorial habits. Ravens mate for life with one bird and take up a territory they feel is big enough to raise offspring for the rest of their days. Ravens are not mature enough to mate until 4-5 of years of age so young birds will gather in small flocks and hang out on edges of territory belonging to others, savaging and stealing food, sheltering, etc... until they are old enough to take find a mate and find their own territory. Pairs that own territory remain in their area, guarding it from other pairs of Ravens. They do allow others to winter over if the territory is large enough.

Crows on the other hand are highly social, gather and live in large groups, they do not mate for life and breed with many others in the group. They nest up together, helping each other to raise offspring. They migrate to new territory as a group, depending on food and resources. They are mature around the age of 2 or 3 years.

Two species of Ravens exist here in the US, the Northern Raven and the Chihuahuan Raven.

As for Crows, the American Crow, the Fish Crow, and Northwestern Crow.

 

[centrarchid]

American Crows may need to be further split. Some American crows appear to maintain persistent territories and year round pair bonds. I watch them closely where they can be observed over several years in one location. In other locations they do the large flock formations, most locations where they do not have defensible quality roosting in areas with what appears to be poor to intermediate forage quality.

 

[Trish1974]

I had three crows run off a bald eagle that landed in the tree closest to my chicken run yesterday. Before I could get outside to run the eagle off myself the three crows were on her and drove her off towards the river. Two lost interest and flew off while one lone crow finished chasing her out of view. Wish they were around all the time but I only see them pass over occasionally. If they are chasing off a predatory bird does that mean its the crow's territory, or is that just their instinct to chase off BOPs?

 

[TwoCrows]

American Crows may need to be further split. Some American crows appear to maintain persistent territories and year round pair bonds. I watch them closely where they can be observed over several years in one location. In other locations they do the large flock formations, most locations where they do not have defensible quality roosting in areas with what appears to be poor to intermediate forage quality.

Survival of the fittest I suppose. They will evolve for survival. If there is enough food, I would imagine some Crows might break away and develop different habits. They flock together for more eyes. More food and less eyes are needed. Fish Crows may be a bit more territorial than American Crows.

One thing I have noticed with both Crows and Ravens is differences in language dialect in different parts of the country. They say a Crow from North Dakota wouldn't understand a Crow from Virginia from the varied tones and accents. I hear the difference around here between desert Ravens and mountain Ravens.

I have also noticed in Ravens that the higher altitude they live, the larger their bodies and deeper the croaks and sounds are. Very interesting stuff to study.

 

[Chullicken]

I have the unique circumstance as to have a nesting pair of crows and ravens around my property. The crow's make a tone of racket in the spring, but I rarely see hawks. Which would be ok, all but one of my chickens are kept in a run. Those ravens though..if I leave any eggs out and walk off for whatever reason, they swoop right in and carry them off. I don't care about the eggs so its not a big deal, I just found it one of those really cool life experiences.

 

[TwoCrows]

I had three crows run off a bald eagle that landed in the tree closest to my chicken run yesterday. Before I could get outside to run the eagle off myself the three crows were on her and drove her off towards the river. Two lost interest and flew off while one lone crow finished chasing her out of view. Wish they were around all the time but I only see them pass over occasionally. If they are chasing off a predatory bird does that mean its the crow's territory, or is that just their instinct to chase off BOPs?

It's natural instinct for Crows or Ravens to run off predatory birds from their territory to protect their offspring, themselves, etc... In your case, you may be on the very edge of their territory. While flying through unknown territory, they are less likely to run off Hawks or Eagles if only to protect themselves from an attack.

 

[centrarchid]

A major driver I think for crows to form large mobile flocks is related to Great-horned Owls. During day crows are relatively immune to depredation by wildlife but at night they are extremely vulnerable to owls. It looks like every time the owl gets one, the crow flock roost in a different location until hit by owls again. Where the big flocks form, owls may be less important. Where the crows hunker down in smaller groups, quality / owl resistant roosting, is more uniformly distributed.

 

[TwoCrows]

I have the unique circumstance as to have a nesting pair of crows and ravens around my property. The crow's make a tone of racket in the spring, but I rarely see hawks. Which would be ok, all but one of my chickens are kept in a run. Those ravens though..if I leave any eggs out and walk off for whatever reason, they swoop right in and carry them off. I don't care about the eggs so its not a big deal, I just found it one of those really cool life experiences.

They will steal eggs, even small chicks! But since they allert us with their "Hawks!" calls, they sure are nice to have around.

 

[TwoCrows]

A major driver I think for crows to form large mobile flocks is related to Great-horned Owls. During day crows are relatively immune to depredation by wildlife but at night they are extremely vulnerable to owls. It looks like every time the owl gets one, the crow flock roost in a different location until hit by owls again. Where the big flocks form, owls may be less important. Where the crows hunker down in smaller groups, quality / owl resistant roosting, is more uniformly distributed.

Absolutely!! Everything they do is a survival strategy. Whether they do or don't, depends on the environment and what's in it. Fascinating stuff!

 

[TwoCrows]

Jays, who are also Corvids like Crows and Ravens, will mob Owls and Hawks. I see and hear it a lot around here. 20 or so Jays screaming in a tree and sure enough, an Owl or Hawk comes flying out of it. Ha!