Dennis and the Treehouse is one of a few funny episodes that revolve around Dennis’ tree house. This is the first episode that the house appears in. In fact, Henry and Dennis only get through working on it in this episode. Their construction coincides with Mr. Wilson constructing a dandy bird feeder in his backyard to attract new types of birds. In an attempt to keep Tommy and Dennis from scaring all the birds away with their noise, Mr. Wilson teaches them about bird watching.
As Dennis and Tommy are playing later, they see a bird in the tree house that Tommy thinks looks like the bird in a musical bird cage decoration at their house. It is the elusive Canadian Crested Warbler – a bird never seen in “this” part of the country. The local bird watching club leader even contacted Mr. Timberlake – a big bird watcher to travel down and see the bird. Mr. Timberlake eventually transitions to being a somewhat local character who makes appearances throughout the show – even in the fourth season.
Dennis and Tommy end up seeing that the Canadian Crested Warbler is sick and start to take of it. They then see that it had babies so they borrow Tommy’s musical bird to keep the babies company while its mommy is being treated.
Unfortunately, Mr. Timberlake and Mr. Pomeroy arrive with their cameras while the musical bird is in the tree and accuse Mr. Wilson of trying anything to get on the birdwatcher’s honor scroll (a really high honor). Luckily, Tommy and Dennis were able to overhear this and explain the situation. The two boys and Mr. Wilson all end up on the honor scroll!