There is a purple-bluish "beach" made of mussel shells mixed with bird bones on the west side of the island with some reed grass.

The highest point on the island is usually covered in gull bird guano and is underwater during high tide storms.

[citation needed] Rat Island was included in the purchase by Thomas Pell in 1654.

On September 26, 2011, The New York Times published an article about the island, stating the property would go up for auction on October 2, 2011.

[3] It was sold at that auction for $160,000 to 71-year-old retired Port Authority worker Alex Schibli, a Swiss[4] resident of nearby City Island.

[4] In March 2017, Schibli was sued unsuccessfully in a People's Court episode for fees charged by an engineer whom he asked to give an estimate on what was needed to put a more permanent statue of William Tell on the island.

[1][2] Another theory is that when the island housed typhoid victims in the 19th century it presumably attracted vermin.