Comparing a continuous variable vs a continuous and a nominal

Hi. I'm studying the effect of hummingbird feeders on the hummingbirds' pollinization function. We counted the amount of birds feeding on artificial feeders, and on the other side, we captured a number of birds and collected the pollen they carried, then categorized it in four levels (0 grains, 1-10, 11-30 and 30+ grains).

Therefore, I want to compare the number of visits by species (4) vs the category and quantity of pollen, and see how their feeding affected the amount of pollen they carried. I thought I could use a block model, using the category as block, but the results are not clear, as it seemed to compare only the pollen categories. So I'm not sure if I should use the block model.

I'm using JMP for the analysis. Any help will be much apreciated.

Many thanks, and sorry for my english.