UICollectionView: number of cells visible

Question

When I print the number of visible cells in my UICollectionView and the array counts it by one. The number of visible cells is lower. Any ideas?

NSLog(@"visibleCellscount %d",self.collectionView.visibleCells.count); (visibleCellscount 2) NSLog(@"birdscount %d",self.birds.count); (birdscount 3)