tracking birds

My son feeds the local geese and we saw one with an orange band around its neck.
Obviously tagged.

He wants to know if anyone can buy a tracker device thats put on animals.

It would be illegal to band or “tag” a bird unless one is a permitted bander. The banding of birds is controlled by the Migratory Bird Treaty Act and as such one must have a federal banding permit. Many states require an additional permit as well.

There is a lengthy process involved in becoming a master bander. Additionally, waterfowl is only banded by federal agencies.

Falconers frequently attach miniature radio transmitters to their birds. One common kind attaches to a tail feather shaft near its root and trails a short antenna wire; it weighs less than an ounce, including a small battery that will transmit for up to a few days. A bird that weighs a couple of pounds or more will scarcely notice this.

But such transmitters aren’t cheap, and there are both legal and logistical issues in catching wild animals and attaching things to them.