any ideas will be appreciated

Sophie, my almost 2 year old Ruby Cav, has this odd behaviour.

I have a bird aviary up the end of my back yard.
Sophie runs out the back door as soon as anyone opens it and proceeds to jump up the side of the aviary and snap at the poor birds. She seems to think this is something that would make me proud.
So I have ignored the behaviour, yelled at her (which I know is wrong).
I try to call her away, and she just ignors me. She is so stubborn!
This all started when another Cav visited and showed her how to to this. They thought it was a good thing to do.
Not only is this bad for the birds, but she could hurt herself, my worry is she will get caught in the wire.
Any ideas? Please!

Yes. You will need to not give her access to the aviary, simple as that. Either fence it off so that another barrier prevents her from getting that close (which is what I would do); keep her on a lead outside a all times; or really focus on obedience work with her so that she knows to respond to your cues and will stay at your side or return when called. Or a mix.

Her behaviour isn't odd -- it is pretty normal for a dog seeing a group of birds! Cavaliers are spaniels and many have a very high prey drive that is entirely instinctual and can kick into play any time (it may have been the other dog showing her what fun it is to go for the birds, but very likely she would have figured this out herself in time). In addition birds are often just a temptation anyway, like squirrels -- they are small, active, and attractive to a dog. They get them excited and they bark and want to get at them.

Remember a dog can only be expected to do what it has been trained to do by us, and training takes time and effort, and isn't a quick solution -- but it should be part of your solution. You ideally need to be able to have a dog that responds to being asked to stay close to you, which can be recalled immediately, and which will go into a polite downstay (these are all training issues that will take weeks to months to accomplish). But the simplest and most direct solution in the interim (and permanently), would really be to fence off this enormous temptation -- that is the responsible approach to take both for your cavalier and for the birds, who must find it extremely distressing to have a dog leaping and barking at them. Once you own multiple animals you end up with a much greater caretaker role as they will not necessarily have any interest in cohabiting peacefully (and certainly it is not in the nature of most dogs to think birds are not a form of prey). You as the caretaker need to make sure all are safe and comfortable.

Hi Sharon

As annoying as this is, she really is just being a dog, exercising her prey instinct. So it really isn't odd, but of course it is not acceptable. Obviously you don't want her doing it as you have already said, it isn't good for the birds and she could hurt herself on the wire. The way I see it you have two options. One is to organise a barrier so she can't get near the aviary and the other is to use behaviour modification.

Is it possible to erect a fence around the aviary so she can't get to it?

As to the behaviour modification, well you can teach her to leave the birds alone. We actually have quite a lot that come & land on our veranda for a feed, and our dogs know to leave them alone. When my dogs were puppies I would issue a sharp "ah! off!" command if the dogs approached the birds. As soon as they obeyed I would give them a treat & heaps of praise. I can now have the birds sitting about 1' above the dogs heads feeding, and the dogs just looking up & catching any crumbs that happen to drop down. It does take time, but with persistence you can do it.

Thankyou for the great advice. I had never thought of it that way, that she is just doing what is natural to her.
Building a barrier is out of the question. I would do it if it were possible, that does make sense.
I will have to try some intense training.

What about something as simple as an x pen type set up to fence off the birds ? Just as a temporary measure to break the habit ?

Also I would use something (high value food or fav toy) much more interesting than the birds and use it as training to distract from the routine of going striaght out there and teaching a strong leave command ??
Maybe even make your baby wait at the door before being allowed out so she has to insert patience and again break the habit of bowling out ?