The tree silhouette is not linked to the source file. Look at the Links Pallet and click on page number will show which image is missing. Can Relink the file in Links pallet if the file is available.
This font colour is Registration Black so exceeds 300% ink limit and may not dry and if off register would be unreadable (picks up 100% CMYK plus any spot colours (all printing plates) in the swatch)
Two Pantone colours too many in the Swatches pallet, the bottom two colours do not show on the Separation preview. Delete any unused Spot colours in your swatches pallet.
The resolution should be 300dpi not 72 dpi. To correct would need to rescan the image cant correct the original image in Photoshop.
Bird 1 has an effective PPI of 1897 so a large image was scaled down to 15% in Indesign. We can edit this in Photoshop by applying the 15.8 scale so we get the actual photoshop image in Indesign. The consequence of scaling down is that we are working with unnecessary large files. Also Indesign has to work harder to scale down which can lead to printing errors.
No bleed on the first page. (Press W to see all margins)
A RGB colour on this tiff. In Photoshop Use the Gamut warning can adjust the colour hue or just convert to CMYK
RGB blue has been used Would be converted to CMYK during the print process so his may lead to unexpected results. Double click on swatch and change to CMYK