Thanks birdguy. Since time was of the essence, I looked further online and was able to find a NY State Wildlife Rehabilitator and got her on the phone. I was only seeing one Robin adult on the ground, sitting in the corner of the garden below the pear tree. It had been sitting there for several minutes, which seemed odd. I had seen either this one or another hopping around, but for over an hour there was no adult getting INTO the tree and taking care of the one hungry chick I could see. She recommended that I go outside and walk near the adult that was sitting in the garden to see if it would fly to the nest or away. When I went out to test the situation, it hopped away and hid under another bush as I approached, and I could see that one of the wings had feathers askew. The rehabber thought that I should get a towel and try to bring both the wounded adult and the remaining chick(s) to her house where she rehabbed many birds, since nobody was getting into the tree to feed the chicks and the adult may also be in danger. I went into the house to get some boxes and towels (she recommended separate boxes for the chick and adult to reduce stress on the adult), came out and the adult was no longer in the area. Perhaps he/she was just mildly injured and could not make it into the tree, but could fly or hop away to a more secluded spot to recuperate and rest. At any rate, no adult Robin was in the picture, the chick had not eaten in some time, so I got up on a stool and took the nest down. As I suspected, there was only one chick in the nest. It was only partially covered in a soft downy fuzz and was mostly pink and grey. So, my suspicions that there had been some sort of battle for the nest and chicks the night before were correct. Two chicks were taken, and either the parents had decided to abandon ship or were injured beyond ability to care for the remaining chick. Perhaps that injured adult that was hanging around was hoping to get the strength to care for the chick, but was unable to do so. I feel that somehow I was meant to see the situation. I took the nest in a towel, covered the top (left space for air) and put it in the box gently, and hit the highway to get to the rehabber. I could hear the chick chirping occasionally, and from time to time it would lift its head with open mouth waiting to be fed. It was heartbreaking. At every red light I looked down to confirm that the chick was still breathing, which I could easily see through the gap in the towel. I got to the rehabbers house and she couldn't be nicer. She had many small chicks of all varieties in paper towel-lined baskets in bins, with heating pads underneath to keep them warm. She immediately gave the chick some fluids with minerals subcutaneously, and said that you have to wait a while for that to take effect before giving other foods or the chick would not digest the foods properly. I had to leave shortly due to some business, but I'm waiting to hear if the chick made it through the day. The rehabber said that some chicks will make it for a few days, but then will fail to thrive and not make it, so I think she was preparing me for a 50/50 chance. The rehabber told me that every spring and summer she gets many Robin chicks with deformed feet, and that she suspected lawn and garden chemicals since Robins eat mostly worms and other insects that may have consumed these chemicals as well. She said that veterinarians always dismiss her theory about the chemicals, but I don't! I resolve to stop using any lawn chemicals from this day forward (my garden areas are already chemical-free). I have learned a lot from this episode, I hope the chick makes it, and next time I hear such a screetching sound and a nest is reachable, I will not hesitate to help if I can help. I feel so bad for the little family that I photographed so happily the day before. I know it's nature's way and that not all chicks will make it, and that there are eternal rivalries for food and territory among and between species, but it's still sad this evening when I look out the kitchen window and don't see the nest, the attending adults, and the chicks. Perhaps I'll prune the branches of that pear tree to discourage other robins from using it, as this is clearly not a good territory for them to nest in with so many bluejays and starlings around. Thanks again birdguy.

Sulfur odors can be tricky to track down. They don't show everywhere. Odors can indicate in showers due to the aeration of the water spray. And not in every shower. Sometimes only in a shower higher in elevation. Depends on how the plumbing is run. If you have an electric water heater, the basic remediation I advise is to drain and flush the water heater. Pull the anode and inspect it. Replace the anode with a non-magnesium anode. Refill the tank and hold the water overnight at an elevated temp. Most water heaters you can only go 140-150 degrees or so. Turn off the heater, and again drain and flush the tank. Refill and see how things turn out. If you still have an odor after that, then it's time for a chlorine shock. But usually the first part does the trick.

It is very likely that I had "weeded" this out the last few years not knowing what it was. It is in our front, south facing flower bed. We have lived in our home for four years. The first owners of the home had done an amazing job on landscaping (15 years mature) and I have been inspired into gardening because of it. I'm fairly a newbie, having only owned land for 4 yrs and in a totally different climate zone from where I grew up (South Florida). I'm am learning a fairly rapid pace however. I'm glad I hadn't weeded this yet, and I hope to see it bloom. It has never bloomed while I have lived here possibly because I have been pulling it out! I will post pics if it blooms.

I wish I could see the sawfly in my photo you refer to, but I can’t. Nevertheless, I’m going with the sawfly as the culprit and will act with some haste tomorrow because the damage seems to move pretty fast to serious. Funny how someone like myself can suddenly experience a problem after 45 years of growing roses and never before see the problem. Thanks so much for all the good responses. I was lost For a solution.