"As late as necessary contraint"

I definitely recommend do not use ALAP in this case, and reserve it for those very few rare circumstances where it is really useful or necessary (almost never).

You have seen how it works, and people usually think it means the same as zero free float (slack), which it is not. It sucks all of the total float (slack) out of all of the successors.

I also recommend not using weird links, like SF and lag, especially discourage negative lag.

Make that manually scheduled task auto scheduled.

Schedule everything, including the land clearing, ASAP which is a basic characteristic of Critical Path Method. Then you will know the early and late starts and finishes, free float and total float. See the schedule table. If you switch to the detail Gantt view you can see the total float on the bars in the chart.

Make a task calendar which restricts the available dates to the non bird protection periods, and assign that calendar to the land clearing.

Make a 7 days/week calendar and assign that to the recurring bird protection period.

Now you can choose any date between the earliest star and latest start  as the intended date to start the land clearing.

Here is a picture.

Any help?