Answer
The sun is now higher in the sky.
Work Step by Step
As the shadow moves up the wall, $\frac{\Delta y}{\Delta x} = tan~\theta$
Let $v_y$ be the speed of the shadow up the wall.
Let $v_x$ be the speed of the hawk.
Then:
$\frac{v_y}{v_x} = tan~\theta$
$v_y = v_x~tan~\theta$
$v_y = (15~m/s)~tan~\theta$
If $v_y$ increases, then $tan~\theta$ must have increased, which means that $\theta$ must have increased.
The sun is now higher in the sky.
