Matrix models are used extensively in demography and population biology. The example discussed here shows how a simple 2 × 2 matrix may prove of use in the study of bird populations. Teachers may find it an interesting illustration of the application of matrices. The knowledge of matrices that is required to appreciate the model and investigate it numerically may be summarised as (1) the expression of two linear equations as a matrix equation, (2) the multiplication of matrices. A deeper understanding of the behaviour of the model comes from the use of eigenvalues.