Before the 1940s you would only see house finches in the south-west of North America, States like California and Arizona, and in the west of Mexico but now you see them everywhere in North America and Hawaii.
This is in part thanks to a pet-shop releasing several house finches in New York and to their penchant for ‘’spreading their wings’’ into new places. Although typically they are not migratory, in the Eastern populations some individuals migrate.
Migratory behaviour in birds can evolve fast taking only several generations. Some individuals migrate while others stay put, but even those that migrate can have a ‘’staycation’’ some years. It seems that being able to migrate, even if it is short distances to a neighboring state, helped house finches to spread far and wide.
This may have been to the detriment of the purple finches who were outcompeted by the introduced house finches. Both finch species feed on seeds and fruit and will visit feeders. It is more likely that you will stumble across a purple finch in the woodland.
There are two subspecies of purple finches: one can be found on the east of the Rockies and on the west in North America. Like other animals that live at high latitude, glaciation events forced species to shift to survivable areas that are not connected thanks to the physical barrier of the ice sheets.
This happened to purple finch species over one million years ago and the two subspecies went their own ways. They can interbreed but only in areas they overlap, which happens rarely, since they now behave and even look slightly different from each other.
The Eastern subspecies migrates more than the Western and their songs are also different which may further prevent them from breeding with each other since they do not share the same taste in songs.
House finches, whether male or female, are more colorful in rural than urban areas. This pattern is observed in several bird species such as great tits and greenfinches. Living in urban environments can make birds susceptible to disease as cities can be stressful, busy places full of close interactions with others.
Male house finches that live in cities have more intestinal parasitic infections compared to their rural counterparts but surprisingly this is not true in females. Females may have better immune systems or experience less stress than males in an urban environment. They do out rank males at feeders where they will get first dibs of tasty grub.
House and purple finches look very similar but if you take the time to focus on certain characteristics, you will be able to tell them apart.
What is the difference?
Females of both species are both brown with darker streaks or lines all over their body and head. Female house finches can also have a patch of red or yellow on their rump. The most obvious differences between female house and purple finch is in their streaking pattern and face.
House finches have faint almost blurry streak patterns all over their body compared to the purple finch females whose streaks are bolder and well defined. With a pair of binoculars or if you are close enough, you may spot the white eyebrow and white mustache-like line and dark brown cheek of the purple finch which the house finch lacks.
Male purple and house finches are both brown streaked with red-pink stained heads and breast and paler bellies. Male purple finches have more red staining on their faces and red staining on their backs which the male house finches lack.
Instead, the house finches have brown cheeks and necks and brown backs. To confuse things further, some male house finches can have yellow-orange staining to their head and neck instead of the red-pink colouration, but at least those individuals are easily distinguished from purple finches.
Next time you spot a brown streaked finch, whether it is female or male, and unsure of whether it is a purple or house finch, remember, their differences hide mostly in their cheeks.