Mates For Life?

Crane mates dancing to reinforce their pair bond
Photo: Sue Kersey
Whooping cranes normally mate for life. Are there ever exceptions? When Journey North asked biologist Tom Stehn that question, he answered with an interesting story. A pair of whooping cranes in the Western (Aransas/Wood Buffalo) wild flock shows that "divorce and reconciliation" can happen among whooping cranes!

It is thought that divorces sometimes occur among whooping crane pairs when they are unsuccessful at producing young that survive. This is a survival instinct. Mr. Stehn tells how it worked for one crane couple known as the "North Pipeline Flats" pair. This pair was together for 5 years and never produced a chick that lived more than about 3 months. Mr. Stehn tells their story:

Home in the Pipeline Flats
This mated pair is formally called the "North Pipeline Flats" pair because their winter territory is located on some large, shallow wetlands (called tidal flats) located on the north side of a natural gas pipeline that crosses the refuge. In Canada, they nest along the Sass River in Composite Nesting Area (CNA) #19.

The pair nested together starting in 1991. Although they hatched chicks in 1994 and 1995, they weren't successful in keeping them alive and bringing them to Aransas for the winter. Thus, this lack of success may have led to the "trial separation." This happens much more frequently with sandhill cranes. Sandhills that aren't successful breeders will usually switch mates until they are able to raise young.

Separation and Reconciliation
During a trial separation from fall 1995 through summer 1996, the male crane resided on this territory with a younger, unbanded bird. His former mate hung around, but she kept getting chased off by the new female. The newspapers picked up the story and called it the "whooping crane divorce." Well, the saga may turn out to be a "trial separation" rather than a divorce.

Together Again. . .and Raising Chicks!
The original pair was apart for about a year. They even migrated separately in the fall of 1996. Imagine my surprise when I found them together again on their former territory here at Aransas NWR in November 1996! Their nickname is now the "reconciliation" pair. They nested together in 1997, 1998, and 1999, and brought chicks to Aransas in two of those three years. They did not raise any chicks in 2000 or 2001, but succesfully brought a chick to Aransas in both 2002 and 2003. Thus the North Pipeline Flats pair became one of the more productive pairs.

It took twice, but they're mates for life.*

Tom Stehn

USFWS Whooping Crane Coordinator (retired 2012)
Aransas National Wildlife Refuge
Austwell, Texas

*Tom Stehn's 2007 UPDATE: We checked with Tom for an update. He said, "Whooping cranes get old. The North Pipeline Flats pair survives no more. Male BwB-YbY died in winter 2005-06 (I think I recall December 2005 when he went missing, leaving the banded female and chick on the the Texas winter territory). The chick also died later that winter while at Aransas.

"The female may have nested in 2006 at nest #18 in Canada, though we never saw the remaining color band (white on her left leg), so we can't be sure it was she that was at nest #18-06. She did not show up for winter 2006-07 at Aransas and the N. Pipeline Flats territory is vacant. If alive, she would have had to lose her color band and be gone to another winter territory. At best we have to consider it an unknown situation, but we have to theorize she also probably died."