Certain unadapted varieties will never mature the fruit regardless of the management program. Spray when the first leaves on the tree reach full size with second spray in 3 to 4 weeks. Be sure to get good leaf coverage with spray. Those birds have keen eyes and know exactly when the figs are ripe. They don't wait until the fig has softened and you had better not either.
Figs are ripe when they turn from green to brown.
As fruit ripens, it will also spoil and be invaded by weevils. The best strategy is to get the fruit as soon as it is harvestable. Unfortunately, figs do not ripen further once harvested and will only keep a few days in the refrigerator. The only surefire way to keep the birds off of the fruit is to cover the plants with bird netting which is available at various garden centers. Also, only plant closed-eye varieties such as Alma to preent wevils from getting in and souring the fruit.