Rest in peace.
Death is unfair, painful and scary. It doesn't matter if it's just a little sparrow or squirrel or a friend or family member. Death sucks.
A friend of mine learned a classmate from high school died recently, and he didn't expect it to affect him as significantly as it did. Another friend accidently killed a squirrel while driving, and, again, he didn't expect it to affect him as significantly as it did. An owl ambassador died, deeply affecting many of my friends and former coworkers. That owl's death also affected me more than I thought: though I didn't know him I had met him; he was the last animal ambassador I saw before I left the Park.
Then today was my first day volunteering for Project Wildlife. While feeding my last cage of baby birds one just wasn't interested in eating. I notified a manager, handed over the tiny guy, and she said she had to euthanize him. He and his cagemates had conjunctivitis, which is pink eye in humans but in birds is a virus that might never go away. Acute cases are euthanized. A minute later another bird started sneezing so again I called over the manager. He wasn't even opening his eyes, so she took him away too. Then she saw the eyes of the other 2 birds in the cage and made the decision to euthanize them all. I'd just been feeding them for 5 minutes and was already attached enough to be sad at their deaths. I knew it was for the best- no reason to prolong suffering and waste our resources on animals that won't survive anyway, and keeping them alive was putting nearby cages at risk. But I was still sad for their tiny lives. It made me think how much we are affected by loss of life- if these little song birds made me sad, how sad are my friends who lost their owl, and how sad to know you killed another animal, and how sad to lose a person.
Maybe we're all selfish and want whoever died to remain in our lives to fulfill whatever role is now empty. Or maybe we know we await the same end and being reminded is just too scary. Or maybe we think it's unfair that the deceased didn't get to live longer. Whatever psychology you choose, death is not easy to handle.