Planting a small evergreen tree inside a backyard aviary; advice needed

postlapsaria

I recently built a split outdoor flight pen to house two different species of quail; each side of the pen is about 12 feet long, 6 feet high and 4 feet wide with wire serving as the walls and ceiling and the grass/dirt ground serving as the pen's floor. Pictures of it are attached below.
I'd like to plant a small evergreen tree in the left side of the pen (the side with the blue tray in the pics) to serve as a perch for the birds as well as to provide a more natural habitat for them/a more natural aesthetic for the pen and was hoping to get some ideas of what type of tree would be best suited for the job.

Here are the requirements/preferences:
-I'd rather not use a deciduous species as I'm assuming the quail would be tempted to eat off all the leaves
-The tree has to be able to be trimmed back without significant damage once it begins to outgrow the confines of the pen
-It has to be able to survive in partial shadow; the pen and the canopy of branches overhead keep the inside of the pen about half in sun and half in shadow throughout the day
-I'm looking for something with sturdy branches that wouldn't immediately bend over once the birds try to perch on them
-As far as size goes, narrow is better, and something around 2 feet wide and 5 - 6 feet tall would be ideal
-I live in Maine, so it's got to be able to survive this climate

I asked at a local nursery and was told that pine and spruce trees wouldn't be a good choice because one needs full sunlight and the other would die if I were to trim off the top once it vertically outgrows the pen (I forget which was which). They recommended Arborvitae, which looks good, but because of how dense and close together the branches are I don't know how well the birds would be able to perch on it...also, the branches don't appear to be terribly sturdy for holding up their weight. What else is there that would work in this situation? Any other info or advice in general would be appreciated as well.
Thanks for reading!

Attached Thumbnails

 

derwoodii

Wow not an easy one. Perhaps try a few semi advanced tree shrubs in pots 1st. See how they go n see how your critters enjoy them. If one or two prosper plant em. As you would visit the coup often water and plant care would not be a chore.
Ask nursery for local indigenous shrubs that favor sub canopy of forest Take care some that may have harmful effect on birds.

My wild card guess plant is Kumquat will go well in pots has other nice attributes kinda like your chasing.

Kumquat - Wikipedia, the free encyclopedia

treeshaveneeds

Common Yew (Taxus sp) will do what you want, but will take time to have the sturdy branches the birds need (all trees/shrubs will have the same failing until 4-5 years hence) and perhaps Hemlock (Tsuga sp) I doubt the quail will eat the foliage, but if so all parts of the yew are poisonous except the red berries. If you choose a yew, gets a Hick's Yew (variety grows tall, vs wide); if choose Hemlock, try to get a columnar variation.

postlapsaria

I ended up getting a Thuja Occidentalis Nigra (Arborvitae/White Cedar) that seemed like it would be about the right size since it was half off for a clearance sale, but now I'm not so sure about using it after reading on the following sites that it is toxic:
Talking Green Parrot - Plants Which are Harmful to Birds
Toxic
http://www.mnpoison.org/mnpoison/pdf...uideJuly04.pdf
STIHL - Encyclopaedia of trees - American Arborvitae, White Cedar
http://www.thebirdwhisperer.org/plants.pdf
http://www.ohsu.edu/poison/documents/plantsVeryBad.pdf

However, this one site has it listed on the "Bird Safe Trees" list:
Toxic Plants

Still, I'm a bit hesitant about using a tree listed as toxic in there, especially since the quail won't have much else besides dirt to peck at so I can imagine they might eat at the arborvitae out of hunger or boredom. Any input? Am I just worrying too much?

The only evergreens that I've consistently found on the "safe" lists for birds/aviaries so far are Pine, Fir and Spruce. Would any type of pine, fir or spruce be suitable for this environment/meet the requirements? I was told by the people at the nursery that pine and spruce wouldn't work, but that was in reference to the specific type they had there so I'm not sure if it would apply to other types as well and I didn't ask about fir.

treeshaveneeds

Most conifers want full sun - pine, spruce, fir, cedar to grow best - both yew and hemlock will tolerate shade. I wouldn;t really expect your birds to eat the foliage, most birds don't. If they are that hungry, feed them more, then they'll see the trees as protection -- the natural response. Both cedar and yew are poisonous, but mammals have to ingest quite a few leaves/needles. I really doubt the quail would want to. The cedar may have been half price, but it will not be strong enough to hold a lot of birds until it becomes established. Many people think cedar grows well in shade -- it does not; like most conifers, it does best in full sun.