The White-throated Sparrow breeds in the Boreal Forest and edges south to transitional forests, but is overall a rather northern breeder. In winter however, this species invades the south and becomes one of the more common wintering species throughout much of the Eastern United States. Some reach south to northernmost Mexico, and it is rarely encountered in the northern Greater Antilles. This is not a very southern migrant. Therefore it is amazing that it has wound up as a vagrant on the Dutch island of Aruba, which is in South American waters immediately north of Venezuela! The White-throated Sparrow comes in two morphs, a bright “white-striped” morph and a duller “tan-striped” morph. The relationships of these two morphs, and their correlation to behavior is quite amazing. For example male white-stripe birds are very territorial, aggressive and spend very little time caring for the young or nest; opposite to the tan-stripe males which do help at the nest and spend much less time singing and being territorial. Similarly the white-stripe females are more aggressive and less attentive at the nest than tan-stripe females. In the breeding grounds the morphs are negatively assortative, in other words a male white-stripe tends to mate with a female tan stripe, while male tan-stripes tend to mate with female white-stripes! If a male and female white-stripe wound up together, no one would be very good at caring for the young, so mixing up the morphs makes a great deal of sense.