• BirdForum is the net's largest birding community, dedicated to wild birds and birding, and is absolutely FREE!

    You are most welcome to register for an account, which allows you to take part in lively discussions in the forum, post your pictures in the gallery and more.

Eagles eating more geese in Eastern Passage or I just notice more? (1 Viewer)

I like in an area that has had lots of Canada Geese and a good number of Eagles for 11 years now. It's the first year that I'm hearing lots of reports when I'm out talking to local people about the Eagles killing ducks and geese. To me it seems unusual but maybe I'm just talking to more people? What are your findings? My stomping grounds are Eastern Passage and Cow Bay area.

What makes the Eagles change their eating patterns? I always blamed the practice of feeding them chickens but I think that may not be the factor I thought it was.
 

lochjohn

New member
Eagles' food

Hi. As far as I know, Bald Eagles will eat most anything, including Osprey chicks, loon chicks as well as dovekies, frogs, gophers, fish, salamanders, etc.
 
thanks John - makes sense - all those critters are way smaller than a Canada Goose - I'm just surprised they would take down something so large - well never a dull moment in nature!
 

njlarsen

Gallery Moderator
Opus Editor
Supporter
Barbados
Their European counterpart has been seen taking Great Black-backed Gulls for example. The thing with geese is that flocks often work by protecting each other. Is there a chance that the geese being eaten were already dead or significantly weakened before the eagles got involved?

Niels
 
Wow...I can't imagine any bird taking down a Great Black-backed Gull. Those guys are brutal. I've seem them kills ducks by smashing them on rocks. I wonder the same about the Geese here. Something is going on. Maybe something is weakening their population. We have a good number of Raptors in the area, Rough-legged Hawks and Short-eared Owls to name too...maybe other things are taking a swipe at them. Although they've been around every winter for years too. I'd be more inclined to think man-made issue such as a pesticide on the golf course or something. When animals start dying, I usually blame people. We may never know but I'll keep my thinking cap on and observe more closely.
 

Hauksen

Forum member
Hi Niels,

Their European counterpart has been seen taking Great Black-backed Gulls for example. The thing with geese is that flocks often work by protecting each other. Is there a chance that the geese being eaten were already dead or significantly weakened before the eagles got involved?

I've seen a White-tailed Eagle land with a freshly caught (and still alive) Barnacle Goose in its talons. I missed the actual strike - technically, it must have happened right in front of my eyes, but with hundreds of scared geese flying around, I probably looked somewhere else at that precise moment.

The behaviour of European geese leaves no doubt that they are scared of flying predators, and here in Northern Germany, it's birders' standard operating procedure to scan the horizon for eagles when a large flock of geese takes off in alarm.

It's my impression that eagles are perfectly capable of catching fit and healthy geese in flight when they manage to achieve surprise.

Regards,

Henning
 

njlarsen

Gallery Moderator
Opus Editor
Supporter
Barbados
Thanks Henning,
when they achieve surprise is to me the point, flocks of healthy geese should be able to avoid most such surprises.

Niels
 

Hauksen

Forum member
Hi Niels,

when they achieve surprise is to me the point, flocks of healthy geese should be able to avoid most such surprises.

Admittedly, I have no idea how often the eagles' attempts fail :)

My impression from observing their flight patterns is that eagles apparently like to check out interesting birding sites from some height and a fair distance, and then come back later, approaching at a fairly low altitude using ground cover (like dykes) to break the potential prey's line of sight.

I'm not quite sure about the height of the dyke in the case of the attack I witnessed, but it might have been 5 m above the geese's eye level, and the geese were about 150 m from the dyke. That equates to a glide ratio of 30, so the eagle could have stayed below the horizon from the geese's point of view only in powered flight, but the gradual altitude loss would still have helped it to keep the speed up.

The time it would have taken the eagle from appearing over the horizon to getting into striking distance to the geese might have been as little as 10 seconds, in which the geese had to recognize the eagle, launch themselves into the air, and gain enough speed and altitude to be able to evade the eagle, who would have come in with enough speed to be quite manoeuvrable.

(There's a biological law that leads to smaller organisms having a better power-to-mass ratio than larger organisms, everything else being equal. I'm pretty sure geese can out-"perform" eagles in the long run due to this, but in the short term, the eagle can use its momentum from the fast approach in lieu of muscular power.)

If the geese manage to evade the initial attack and the eagle expends its momentum, I'm pretty sure they will be able to evade any further attacks easily.

However, while birding, I've more than once been surprised by an eagle "out of nowhere" pretty close by. Good moment not to be a goose! ;-)

Regards,

Henning
 

Hauksen

Forum member
Hi Phil,

Here are some photos that make geese rather unsubstantial as far as the eagles are concerned:

https://www.axel-horn.de/seeadlerjagd/index.html

Highly impressive! :)

Summary of the German text:

- The cranes noticed an approaching (juvenile) eagly and were alarmed.
- The eagle came closer, and the cranes panicked.
- The cranes' reaction was to run around on the ground in tightly packed groups.
- Finally, a juvenile crane took off and was chased by the eagle.
- As the crane just flew straight on, the eagle was able to grip its shoulder and neck. Both birds fell to (or towards) the ground.
- The crane dropped to the ground and cowered. The eagle flew a small circle and landed nearby.
- As the crane was still alive (and from the pictures, keeping its beak pointing threateningly at the eagle), the eagle apparently didn't know what to do and after a while flew off.
- The crane was examined by conservationists. The photograph was at first told the crane had suffered no injuries, but later was informed that it had died three days after in incident while still under observation at the Stralsund Zoo.

Regards,

Henning
 
Eagles hungry here perhaps

Had a good chat with one of our best local bird experts, Fulton Lavender.

He believes if Geese are being actively predated by Eagles in my neck of the wood it speaks to how hungry they must be.

We actually have too many Eagles in Nova Scotia, largely due to an irresponsible (IMHO) practice of feeding them for tourist photos in the Annapolis Valley.

Luckily he says, we also have too many Canada Geese.

Perhaps nature can attempt to balance what man has messed with?

Interesting observations from everyone who replied btw, thank you!
 

Hauksen

Forum member
Hi,

We actually have too many Eagles in Nova Scotia, largely due to an irresponsible (IMHO) practice of feeding them for tourist photos in the Annapolis Valley.

Luckily he says, we also have too many Canada Geese.

That seems to echo a slightly different philosophy from what the German experts usually express. They argue that there's not such thing as a "correct" number for any particular species, and in fact the idea of "regulating" populations is the favourite hobbyhorse of the hunting lobby over here.

Of course, in a different political environment, "too many" can imply an entirely different line of thinking I'd not be familiar with, so that's only an aside on the German state of discussion :)

Regards,

Henning (HoHun)
 

Users who are viewing this thread

Top