According to the Charlton "Canadian Government Paper Money" catalogue, the errors you've posted look to be E3 Offset Printing Errors. They are rare (as most errors are) but there is a problem with the notes' stickers/labels & the fact that many collectors struggle to assess their grade/value.
The 1974 $2 is labelled as VG-F /$450 - a price which is highly arbitrary/inaccurate. A VG note with a 75% offset printing error is estimated to be 15% of $600 or $90.00 according to Charlton. Often a little more will be paid than book (my observation) but I believe that would be a fair price (within reason).
The Birds $20 is similarly labelled incorrectly. While it appears to be 100% offset the amount of ink is fairly light so this will detract from its value (along with its dubious grade). It may be appraised a little higher ($150 - $200) but again- if you were to put error collectors only in the auction this would be only after they inspected the grade of the note (& its eye appeal). Put coin and novice collectors in the auction and the price will likely go double (plus your auction fees/taxes/etc). I've posted my reservations re: auctions in another post.
Personally, I love to collect these notes but the biggest problem is trying to get notes in higher grades priced fairly. Many dealers/collectors don't come across them often and that tends to drive the price up artificially. Once this happens the owners would prefer to recoup their costs so we rarely see notes with errors priced accordingly. I've heard many old-timer seasoned collectors caution that collecting errors should only be done if you "really know your stuff" (including knowing how to identify counterfeit) and after seeing too many errors overpriced, I'm beginning to understand this advice better.