I know exactly when my fondness for wild birds began recalling it was around the time I acquired my 200mm telephoto lens. Up until that point in, most of my camera lenses were for landscape, macro, and wide angle lenses. The outing where I carried my 200mm attached to my camera and I snapped a photo of a small bird perched on a fence line - I was hooked and eventually over time I had acquired longer bird lenses well beyond that 200mm.
Blue Jay's are one of my favorite birds, they are active, smart and boisterous they also understand humans attitudes toward them and learn routines such as putting out food, and they watch with a keen eye.
I have been feeding a group of about 15-20 Blue Jays for at least 10 years. The grouping as I call it to grow and decline from time to time such as spring where the groups tend to be smaller and in pairs of course. During the winter months, the groups who visit my feeder can number up to 20 Blue Jay's as I put out the food.
Observed Behavior Watching the Feeder: I commonly began a regular stocking of food for Blue Jays and other birds as winter approaches. I put out both shelled and whole peanuts and other seed. While doing so I observe one or two Blue Jays watch me then swoop down an take a peanut or two and fly back up into the nearby tree. Shortly after that, the Pair fly off and return along with more Blue Jays in tow. It is as if they go and tell other Blue Jays where the food is, and within a day all 20 show up to enjoy the peanuts.
Routine Visiting Hours: All though there might be plenty of food in the feeder the Jays will disappear for hours. The Blue Jays will normally show up starting about an hour after sunrise and remain to feed for a couple hours then fly off but return again shortly after Midday and disappear again until the mid-late afternoon. Thus their feeding routine appears to be three major sessions each day, occasionally one or two will show up out of the cycle but for the most part that is the routine, I observed. The exception to that is during poor weather be it cold, snowy, or rainy the Blue Jays tend to hang around all day.
Food Preference: In addition to feeding Blue Jays I also place a variety of seed for various backyard birds such as White-Throated Sparrows, Gold Finches, Dark-eyed Juncos, Northern Mocking Birds, the occasional Towhee, and of course Cardinals and a few others.
Shelled Peanuts - This is the Blue Jays preferred food at the feeder. Jays prefer shelled peanuts that are round about the size of a pea this allows the Blue Jay to stock up and load their throat pouches as many as a dozen peanuts in one haul. Jay's behavior with shelled peanuts is to pick up a peanut and arrange each nut to maximize the carrying capacity - if a nut is too long the jay will drop it and choose another, I watch them up to half a minute selecting the perfect peanuts.
Whole Peanuts - Whole Peanuts are a second favorite of the Blue Jays. Like shelled peanuts, the Blue Jay will select the best peanuts from the group. They often will pick up a shelled peanut - weigh it and if too light drop it and pick up another and they do this two or three times when multiple choices of whole peanuts exist. The Blue Jay will also discard the discolored or damaged nuts unless that is the only and last choice.
Other Food Choices: Even though I put out everything from live mealworms, Bird Seed, to shelled sunflower kernels the Blue Jay most always takes the peanuts. I have on a few occasions witness the Blue Jay taking a few mealworms. The third choice of the Blue Jay is the Shelled Sunflower Kernels.
Gourmet Eaters: It just so happens Blue Jays like only the finest and most expensive of foods :0 and with 20 feeding you can go through a lot of food.
Social Habits: I heard others state the Blue Jay is aggressive. Not from my observations, Sure squabbles break out at time but nothing too serious.
Sharing the Feeder with Other Blue Jays: In my many years observing the Blue Jay in the wild and at my feeders, I have never witness overly aggressive Blue Jays. In their own groups when food is plentiful the Blue Jays share and take turns at the feeder without in-fighting. When the Food begins to run short I have witnessed a Blue Jay standing ground until he is finished before allowing another Jay to feed but never with malice to inflict injury to another Jay.
Sharing the Feeder with other Bird Species: This may be why people get the idea the Blue Jay is aggressive. Being Larger does not equate to aggressive - what I mean is as other smaller birds are feeding and a Blue Jay shows up smaller birds will depart. I have never witnessed a Blue Jay threaten the smaller birds. It appears to me the smaller birds are risk intolerant and prefer not to around the much larger Blue Jay. The exception is the Cardinal who will come to the feeder while a Blue Jay is present and take a few bites. Again I have never witnessed the Blue Jay harass other birds at the feeder, but I do know a group of jays will harass Hawks and Crows from time to time. Blue Jays are larger birds so other smaller birds use caution when the Jay shows up at the feeder.
Food Caching: Blue Jays sometime take whole peanuts and fly off into the underbrush and hide the nut, this occurs more often before bad weather arrives, It is like the Blue Jay has a built-in barometric sensor.
Intelligence: I have yet to give the Blue Jay an IQ test but from observation I know they are smart and learn quickly. Over the course of time, a few Blue Jays have come to appreciate me for what I do. In one situation the weather was very poor so and rather go trudge through snow and rain to replenish the Blue Jay feeder I choose instead to lay out the food at the back of my deck. I wiped off the railing and laid out a row of peanuts - The Blue Jays quickly learned this to the point that on occasions when the food ran out - One Jay would sit on the rail and call out until he got my attention and I put out more Peanuts. This jay was literally letting me know the food was gone. I also observe the same behavior when the regular feeder goes empty - a Jay or two will sit in the adjacent tree and call out repeatedly until I show up with more food.
Playing Catch: On some occasions, I stand on the deck with a handful of whole peanuts and alert the Blue Jays by motioning my hand up and down, and then toss the Peanut up into the air - The Blue Jay knows that if he catches the peanut in the air another Blue Jay cannot pick it off the ground before he can get to it. The Blue Jay is quite good at catching
Face Recognition: It is obvious Blue Jays like many other birds know human friend or foe. I witnessed that new Jays will be very flighty when I approach other who know me will simply hang out and over a short period of time the new Blue Jay becomes aware I mean no threat - and begins to approach and take food with I am physically present.
Predation: I read reports some Blue Jays may take others young, I personally have never witnessed that behavior. However, I do have hawks show up after the bird feeders are put out - This particular hawk is a Coopers Hawk and has been visiting for a couple years now in the winter. Unfortunately, as a top predator the Coopers Hawk takes advantage of the situation and I have witnessed the Hawk taking and chasing birds as in the case shown in the photo - Blue Jay was taken by the Cooper's Hawk. One afternoon after replenishing the feeders - the birds normally flock to eat but not this day, I could see them in the brush and inside the tree line. The problem was a Hawk was watching from a perch. It was not until the Coopers Hawk departed did the Blue Jays return.
Do Blue Jay's Mourn? My belief and observation says yes and here is why I think so. A group of Blue Jays were out behind my home taking turns with the feeder, without warning a Cooper's Hawk swooped down and took a Blue Jay to the ground then began the de-feathering process ultimately eating the unlucky Blue Jay. The remaining birds scattered and did not return to the location the remainder of the day. The next morning about 19 Blue Jays appeared in the tree over looking the spot of the feathery remains. The Blue Jays began making calls with some calls imitating the Hawks call, the Blue Jays continued the calls for about 30 minutes and then all but one departed. The remaining Blue Jay was the mate of the one killed who perched quietly and mostly motionless the remainder of the day then returning for the next few days siting over the spot.
In conclusion, I find the Blue Jay a fascinating bird that somehow seems to find new interesting ways to amuse me, although my Bird Food Services can add up but the rewards of watching many birds bring great rewards. The link below is a series of videos about Blue Jays.