Here is a great little trap for the live capture of birds from South America. Very easy to make, even without tools. It is handy to have a piece of string but this can also be improvised from natural materials like spruce roots or bark.
The photos below should be easy enough to follow. You can use a variety of triggers. Here I have used a figure of four trigger. A Paiute trigger also works well. There is also a specific trigger for this trap. Images of this trigger which is not too complicated can be found on the Internet easy enough.
The two anchor pieces / bases are tied together with a piece of cord approximately 1.5 times longer than the base sticks. These are then crossed so an X of string is formed. Sticks are then inserted under the string and forced in tight. The sticks are placed in pairs so that top and bottom are done and then the two sides as shown in the photos below. Eventually it will become harder to get sticks under the string and this is what holds the trap together. The top stick will be the hardest to place. The cage can be adjusted so that there are no obvious gaps.