“…Numerous studies also found that when exposed to artificial light at night, birds show increased activity [ 44 , 55 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ], delayed chirping behavior [ 74 ], increased vigilance [ 75 ] and reduced sleep behavior at night [ 43 , 76 , 77 , 78 , 79 ], but see [ 80 , 81 ]. There is some evidence that these changes in behavior are associated with reduced circulating oxalate [ 66 , 79 ], a biomarker of sleep debt in rats and humans [ 82 ]. However, other studies found an increase [ 83 ] or no change [ 84 ] in oxalate under artificial light at night, raising the possibility that the level of oxalate does not reflect prior sleep/wake history in birds [ 84 ].…”