Eucalyptus oil

Eucalyptus oil is beneficial.

But not to birds.

The oil from the leaves of a few species of Eucalypts are beneficial to humans but bottled Eucalyptus oil can be dangerous to your birds health.
The leaf glands of many Eucalyptus species, especially E. salicifolia and E. globulus, contain volatile, aromatic oils with fever-controlling and germicidal properties. Their chief use is medical, and they constitute active ingredients in expectorants and inhalants. Whilst these oils are good for humans they are refined products and far too concentrated for use around your birds.

Eucalyptus gum leaves which is a great food additive for your budgie

Budgie World makes no attempt to endorse
any health benefits or otherwise from Koala
Brand eucalyptus oil. The bottle image
is merely for demonstration purposes.

click to enlarge click to enlarge

Essential oils are not a source of vitamins, amino acids, or nutrients.
They are isolated, concentrated compounds. They do not have the same
nutritional profile as the plants from which they were extracted.

For the technically minded here’s an analysis of the essential constituents in Eucalyptus oil:

* Volatile oil, the major component of which is l, 8-cineole
(eucalyptol), 70-85%; with terpineole, [[alpha]]-pinene, p-cymene and small
amounts of sesquiterpenes such as ledol, aromadendrene and viridoflorol;
aldehydes, ketones and alcohols

* Polyphenolic acids; caffeic, ferulic, gallic, protocatechuic and
others

* Flavonoids including eucalyptin, hyperoside and rutin.