.bird{
    background-image: url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/174479/bird-cells-new.svg');
    filter: invert(34%) sepia(55%) saturate(427%) hue-rotate(141deg) brightness(93%) contrast(91%);
    background-size: auto 100%;
    width: 88px;
    height: 125px;
    will-change: background-position;

    animation-name: fly-cycle;
    animation-timing-function: steps(10);
    animation-iteration-count: infinite;
}

.bird-one{
    animation-duration: 1s;
    animation-delay: -0.5s;

}
.bird-two{
    animation-duration: 0.9;
    animation-delay: -0.75.s;

}
.bird-three{
    animation-duration:1.25s;
    animation-delay: -0.25s;

}
.bird-four{
    animation-duration: 1.1s;
    animation-delay: -0.5s;
}

.bird-container {
	position: absolute;
	top: 250%;
    left: -3%;
	transform: scale(0) translateX(-10vw);
	will-change: transform;
	
	animation-name: fly-right-one;
	animation-timing-function: linear;
	animation-iteration-count: infinite;
}
	
.bird-container-one{
	animation-duration: 15s;
	animation-delay: 0;
}
	
.bird-container-two{
	animation-duration: 16s;
	animation-delay: 1s;
}
	
.bird-container-three{
	animation-duration: 14.6s;
	animation-delay: 9.5s;
}
	
.bird-container-four {
		animation-duration: 16s;
		animation-delay: 10.25s;
}
/* @keyframes fly-cycle {
    100%{
        background-position: -3600px 0;
    }
} */
@keyframes fly-cycle {
	
	100% {
		background-position: -900px 0;
	}
	
}

@keyframes fly-right-one {
	
	0% {
		transform: scale(0.3) translateX(-10vw);
	}
	
	10% {
		transform: translateY(2vh) translateX(10vw) scale(0.4);
	}
	
	20% {
		transform: translateY(0vh) translateX(30vw) scale(0.5);
	}
	
	30% {
		transform: translateY(4vh) translateX(50vw) scale(0.6);
	}
	
	40% {
		transform: translateY(2vh) translateX(70vw) scale(0.6);
	}
	
	50% {
		transform: translateY(0vh) translateX(90vw) scale(0.6);
	}
	
	60% {
		transform: translateY(0vh) translateX(110vw) scale(0.6);
	}
	
	100% {
		transform: translateY(0vh) translateX(110vw) scale(0.6);
	}
	
}

@keyframes fly-right-two {
	
	0% {
		transform: translateY(-2vh) translateX(-10vw) scale(0.5);
	}
	
	10% {
		transform: translateY(0vh) translateX(10vw) scale(0.4);
	}
	
	20% {
		transform: translateY(-4vh) translateX(30vw) scale(0.6);
	}
	
	30% {
		transform: translateY(1vh) translateX(50vw) scale(0.45);
	}
	
	40% {
		transform: translateY(-2.5vh) translateX(70vw) scale(0.5);
	}
	
	50% {
		transform: translateY(0vh) translateX(90vw) scale(0.45);
	}
	
	51% {
		transform: translateY(0vh) translateX(110vw) scale(0.45);
	}
	
	100% {
		transform: translateY(0vh) translateX(110vw) scale(0.45);
	}
	
}