“The best perches are the natural hard woods such as manzanita, ribbon wood and eucalyptus (very hard when it dries). Other woods may or may not be safe but it is best to stick to one of the three mentioned above.”
– – Barton C. Huber, D.V.M. (Dr. Bart) Basic Bird Care: Avian Health Care Tips

Perches play a very important role in your birds overall health.
Pet bird perches should be of different sizes and irregular. This aids in the exercising of the feet ensuring that muscle condition and coordination does not deteriorate due to lack of foot movement along the perches.
As a general rule your bird’s feet should go 3/4 of the way around the perch but in nature the birds perch on tree limbs of varying sizes. It is recommended that you use two or more different diameter perches. Remember however, that allowing your bird to play on top of his cage or walk on the floor will also exercise his feet
Tough eucalyptus wood makes the best perch your bird could ever have! Budgies love to chew on eucalyptus branches. They provide your bird with a source of stimulation. The chewing activity keeps the bird occupied for hours on end and the eucalyptus oil inside the bark is a natural health tonic. Eucalyptus branches also provide trace elements and minerals that are beneficial to your bird’s health. In the wild, budgies are very active in the morning and evening, but spend most of their day resting in the eucalyptus trees and chewing the branches. Natural (unrefined) eucalyptus oil from the bark is also a germicide that stops diseases of the feet in all Australian birds.
“Eucalyptus branches are nontoxic and are safe to use as natural wood perches.”
– Gillian Willis, Vancouver, B.C.
an “expert” in matters of poisoning and toxic substances

“The most suitable toys for unsupervised birds include natural foods such as grass runners (eg, kikuyu, buffalo grass), various seed pods (eg, melaleuca, hakea, Eucalyptus, callistemon and especially banksia for larger cockatoos), liquid amber, pine cones, vegetables, apple cores, clumps or tufts of grass freshly sprayed with water and short lengths of soft wood with bark attached (especially if live beetle larvae or borers are present). Any natural plant materials provided to birds must not have been sprayed with pesticides, chemicals or fertilizers. Fresh-cut branches from unsprayed fruit trees or vines with the bark intact are favorite treats for birds.”