This analog electronic birdsong generator circuit is comprised of 5 transistor oscillators, several passive filters, and an audio transformer “voice” generator.
I've recently started an experiment with my bees that involves a wood frame and wax foundation in the shape of the United States (lower 48). In two weeks, they've made a lot of progress and show a knack for US geography without any prompting on my part. California and the Pacific NW are extremely popular and apparently too small, as the bees have built burr comb to make the west coast bigger. They have built-up the Rocky Mountains as the high point of their map; and constructed a very large island off the coast of the Northeast. Perhaps an enlargement of overcrowded Manhattan? Otherwise, there's not much happening on the East coast. They've made some progress on the northern section of the Appalachian mountains, maybe a Catskills retreat for Manhattan bees to get away. Florida gets zero attention because the peninsula is too small for bees to make it worth their effort. The Southeast, Midwest and Texas are basically flat but above sea level (if you imagine the wood frame to be their ocean). Nearly all of the nectar and pollen are stored in the bread basket of our nation. Good job little geography bees!