Watch: Barack Obama pardons last turkey in Thanksgiving tradition

President Barack Obama has pardoned his last Thanksgiving turkey, an annual tradition that sees the US leader spare two birds -- the centerpiece of most holiday tables -- from the carving knife.

Obama's teenage daughters, Sasha and Malia, who have stood by his side during previous pardons -- notably casting side-eye glances at their father's turkey-themed puns -- were absent this year.

The festive occasion, rife with bad jokes and poultry photo-ops, saw Obama's significantly younger nephews, Austin and Aaron Robinson, take their place. "Unlike Malia and Sasha, they have not yet been turned cynical by Washington," Obama said yesterday to laughter

"Thanksgiving is a chance to gather with loved ones, reflect on our many blessings and, after a long campaign season, finally turn our attention from polls to poultry," he said as he introduced this year's turkeys -- two 40-pound, 18-week-old birds hailing from northwest Iowa, named Tater and Tot. Tot was pardoned in the Rose Garden ceremony, while Tater was on hand as an alternate, should anything go awry with the main bird.

"I want to take a moment to recognize the brave turkeys who weren't so lucky, who didn't get to ride the gravy train to freedom, who met their fate with courage and sacrifice and proved they weren't chicken," Obama said -- prompting amused groans from the gathering. "It's not that bad now, come on," he quipped. "All right, congratulations," Obama told the crowd after pardoning Tot, as the turkey gobbled on cue.

The president also took the opportunity -- his last pardoning before he leaves office in January -- to check off a list of accomplishments he was thankful for: six straight years of job creation, the stock market tripling, uninsured rates at all-time lows thanks to his signature health care initiative and marriage equality, among others. "Thanksgiving is also a reminder of the source of our national strength, that out of many we are one and we're bound not by race or religion but adherence to a common creed," Obama said.

The origin of the pardoning tradition is unclear -- tales of spared turkeys date back to the 19th-century and the days of Abraham Lincoln whose son, the story goes, convinced him to let a bird live.

John F Kennedy was the first president to formally spare a turkey, in November 1963, but it wasn't until the days of George HW Bush in 1989, that pardoning became a White House ritual.

Thanksgiving is celebrated each year on the last Thursday of November.

This year's turkeys will live out the rest of their lives at Virginia Tech University's newly built "Gobblers Rest" facility in its animal and poultry sciences department.