Nice first attempts :) You do get better with practice.
Some advice: you can indeed use the zoom way beyond the minimum setting. I'd say I can use it with a fair degree of confidence until x35 or so; pass that, I do get blackouts if I'm not ultra-carefull. At that focal length you need more eye relief, which you can gain simply playing a bit with the smartphone (trying no to hold it directly against the eye cover; very flimsy, I know). Alternatively (and low-cost) simply try to use a thick piece of plastic/cardboard (a glass coaster would do) with a hole in it, with this, you gain a couple of mm, enough to regain control and a clear picture (quite vignetted, on the other hand). A much better option seems to be an adapter, Frank can surely give plenty of advice there. :) I'd say past x37-40 you do notice a great lose in quality (specially brightness).
Check the image below, a blackbird around 20 m (60 ft) away. Cropped to avoid vignetting and processed with Snapseed within the phone itself. I guess that was around x30, handhelding the smartphone (Nexus 5; probably a slightly better lens than the Moto E, but worse than any iPhone or the like). Also a nice idea is to take several pictures as burst, since a single one might be blurred, but one will show all the details properly (I had a Moto G, I think that if you kept your finger pressing the screen it took a series os pictures as a burst).
Also the light conditions in the pictures do seem pretty challenging to say the least. I'd say good light makes great pictures when it comes to MM3 and a regular phone :)
Good luck :) Keep us posted.