Although the continental population as a whole remains relatively stable, similar declines have occurred in other Great Lakes states.

The magnitude of the decline is dismally apparent to those who enjoyed the birds’ presence when they were abundant here. In the 1950s it was easy to attract martins even to less than perfect quarters in less than ideal locations. Four colonies thrived within three miles of our farm in east central Minnesota despite red squirrel depredation and house sparrow competition.

Avian experts attribute the population decline to several factors:

  1. Adverse weather conditions during the breeding season

  2. Habitat changes

  3. Nest box shortage

  4. Nest box competitors (starlings and house sparrows)

The validity and relative importance of these factors are uncertain.

Does data support the notion that weather conditions in Minnesota have become and remain consistently less favorable for purple martins than they were in the 50s?

If starlings and house sparrows drove martins from Minnesota, why do martins remain abundant in many southern states where these competitors still bedevil them?

Although purple martins no longer occupy most of the nest boxes offered for them here (east central Minnesota), house sparrows and starlings have not claimed them. Many martin condos now stand entirely devoid of occupants including sparrows and starlings.

John Tautin of the Purple Martin Conservation Association and others believe that martins have declined in part because fewer people install nest boxes these days than in years past.  No doubt fewer people provide nest boxes in Minnesota but the reason is probably the opposite—people no longer provide nest boxes because martins won’t occupy them. Still, the few exceptions to this rule inspire enthusiasts to claim that more nest boxes will save the day.  

Whether the Minnesota purple martin population stabilizes, recovers, or disappears entirely remains to be seen.  Whatever the outcome, we may never know what caused the changes.

                                  Puzzle: Why Has the Purple Martin Population Tumbled in Minnesota?