photo I took of begging child on the streets of Tijuana
step 2 of 6
Next, look through the picture for a shadow that us near the ground, the white arrows are pointing at the trees shadow. Take notice if it is blurry or sharp. Notice that the closer to the ground the sharper the shadow will be.
You will want to make the shadow for the seagull match this part of the tree shadow.
step 3 of 6
Simple Mask (with a soft brush lightly blur the edges with a very quick stroke)
step 4 of 6
Draw a single line next to the line of the tree shadow
Duplicate that layer and move it to the other side of the picture where the seagull will be placed
step 5 of 6
Because the tree shadow is almost perpendicular, duplicate the bird and darken it to black , you can do this by either going the Saturation/Hue and take away all the lightness, or magic wand the area around the bird and inverse then paint bucket it in black
then use the distort or skew to change the angle of the shadow to match the guide lines created in the previous step
Change the opacity to 55% to match the opacity of the tree shadow
step 6 of 6
make sure the edges of the shadow match the edges of the tree, also make sure the top of the bird is bright (dodge tool it lightly if you need to brighten it more, you can also burn underneath him to darken, but his natural lighting would probably be like it is, since he would be hit by the reflective light of ground