Yes, please (YOU, and ALL OF US) make note of date, temperature of water, and which coordinate of the pond the eggs first appear.
My dates have been surprisingly consistent with a big variety of weather leading up to the date. I wonder if it has to do with number of hours of daylight per day or the phase of the moon?
I have had late comers spawn about a week after the first ribbons seen too.
Try to put out some 'structure' including some cavities. Several of us have noted perch finding some kind of housing to spawn IN rather than random branches. I have had them spawn inside my dome shaped minnow nets rather than the branches that were nearby. I also see eggs in very shallow water laying over a bed of oak leaves, usually on the S or SE corner of the pond first.
Water temps and photoperiod are the major variables. Other factors also come into play such as fish condition , population status (most fish try to fill the pond with their kind). The world is full of outlier unforeseen events.
Azteca, my ribbons were strung out over nearly 30 days as well this year, but it seems the largest ribbons were in the middle of that time frame with smaller ribbons everywhere towards the final end of seeing them.
Our first perch ribbons were at 45*F water temp on April 3rd and lasted for 5 days.
We catch the perch for a Mothers day fish fry. We had one 13" perch that didn't lay her eggs but was stuff full of them. She did taste really good. LOL.