Cuckoo clocks haven't changed much in how they work over the centuries. All have a swinging pendulum that counts seconds and all have pipes that signal the hour in the form of the common cuckoo bird call. The materials of the weights and balances may have changed and many are now battery powered, but their basic function remains as they did when they were first created in the mid 1700s. There are two designs of cuckoo clocks which will either be 8-day or 1-day clocks. 8-day clocks cuckoo every hour while the 1-day clocks sound every half hour. The weights that move the traditional style clocks are made of cast iron and are pine cone shaped. Typically there are three weights that work the time mechanism including the pendulum and control the cuckoo bird that pops out on the hour or half hour. While you can still find cuckoo clocks that are ornately carved, more modern cuckoos are design in the minimalist fashion but nearly all of them are made to hang on the wall.

While many diagrams and writings have been found illustrating the cuckoo clock dating back to the late 1600s, the first clock with a cuckoo wasn't actually made until 1740 by a clock maker from the Black Forest named Franz Anton Ketterer. These clocks became known as Black Forest Cuckoo clocks, named after their place of origin. While many historians contest the idea of Ketterer being the first cuckoo maker, the fact is that the Black Forest Cuckoo clock became very popular in this region and was made into a thriving industry. The most regarded clocks of this type today are still produced out the Black Forest.

There are around a hundred licensed clock makers in the Black Forest today, but only a few have been successful enough to achieve international notoriety. Harvesting the Linden wood has become a full time, year round endeavor for these companies where once it only occurred in the months of winter. Of course, the modern cuckoo clock is made to fit the modality of current styles of minimalist décor. Flat surfaces with simple design, geometric shapes are all common practices among modern clock makers, however there are a few loyalists who continue to produce ornate facades reminiscent of the old German cuckoo clocks of the Black Forest. These companies include Dold, Herr, Jaeger and Schwab.

Chalet cuckoo clocks are modeled a wooden huts and have steep slanted roofs and may have other figurines besides cuckoos come out of the clock when the hour strikes. Made popular by the Swiss in the nineteenth century, typical cuckoo clock parts include wood cutters and beer drinkers and plays music instead of cuckooing. There are three main styles of the Chalet cuckoo clock and they are the Brienz and Emmental of Switzerland and the Bavarian chalet.

These are the antique cuckoo clocks that everyone is familiar with. They require winding every 30 hour and on the hour a cuckoo pops through a small door and signals the time with as many cuckoos as the hour. At the half hour mark the bird will come out and give a single call. Two weights hang unevenly; one winds the clock mechanisms, the other manipulates the cuckoo's bellows and pipes.

There are eight day clocks that work the same as the one day clocks but the weights are heavier and require the clock to be wound only once every eight days, hence the name.

These clocks work like the one day clocks but they utilize a third weight to work a music box made of a rotating drum that is pluck by the weight. This Swiss music box plays a short melody after the cuckoo bird signals the hour. Two melodies are played; "The Happy Wanderer" to signal the hour and "Edelweiss" to mark the half hour.

As with 8 day cuckoo clocks there are also eight day musical cuckoo clocks that have heavier weights, three of them and the music plays only on the hour. Nothing is played on the half hour. These clocks often have figurines as described above instead of cuckoos.

Below is a classic example of cuckoo clocks done in the Chalet style with a music box.