Dana, don't be disheartened because you asked a perfectly valid question about trying to look after your birds even better than you are now. I looked into this exact same issue for my birds several months ago. However, I'm not going to send you via the cape looking at articles, blogs or links. Instead you and I are going to consult an old friend of mine, whom you and every other member here also knows. As unbelievable as it may seem, the famous Nuclear Physicist, Dr Albert Einstein is going to contribute to a thread on Avian Avenue and assist you and I to solve "Dana's Dilemma". Now I'm tipping that it is quite possible that the good Doctor knew absolutely bugger all about birds, but he sure knew plenty about the properties of light and it is primarily his work upon which all current formulae regarding the calculations of the various properties of light are based.Back to square one. Phooey! The cage mounted type is not a good option, for the info provided from Laselva and because I have playtop cages so it would be a PITA to put them on and off..the swag light thing won't work because my cages are really tall and close to the ceiling. The only other option is the freestanding lamps but for my two cockatoos that's going to be tricky because I am using all of the space available on the wall where they are for their cages..no space left. So that means actually putting the lamp in front of the cage..awkward. The space they are in does not get very much light from the windows.
My birds get outside on the porch at least twice a week from 3 to 5 hours or more each time. They have not been out during the week lately because it's been so hot here and still sweltering when I get home from work so they are down to weekend mornings. I need to add more light to both rooms where my birds are so I thought that if I am adding lights specifically for the birds I may as well go the FSL route.
Something tells me I am going to still be unable to decide and then do nothing.
See, I promised he would make an appearance just for you. Now to make this a bit of fun, I want you to imagine that you are sitting in a physics lab and you are about to be briefed by an elderly, well spoken gentleman with a European accent wearing a white lab coat, Dr Albert Einstein himself and I shall pretend to be the good Doctor (I wish). Are you ready??? Here we go.
"Guten Tag Dana. Stormcloud has briefed me on zie nature of "Dana's Dilemma", but I believe I can provide an answer for you. LaSelva is quite correct in pointing out zat zie globes, or bulbs, vitch ever is your preference to describe zem, are quite veek regarding zear output of both UVA & UVB category light spectrums. Even if vee use zie reflector specified by zie manufacturer to concentrate light output to a given focal point zie light vood have to be positioned quite close to zie bird. Vee are talking about a distance of 150-200 millimaters, or 6 to 8 inches, for zie light to have zie desired effect. If vee need to have zie light positioned zat close to zie bird zen vee are probably risking eye damage, zuch as catarats, to zie bird. Zear are many variables at play here, such as vear zie bird is positioned in zie cage. Sometimes he vill be at zie top, and sometimes he vill be at zie bottom, but vee do know zat birds tend to perch in a higher place zan a lower place as zay feel safer zear. Since your cage is very tall at 1800 millimaters (6 foot), vee shall assume zat your bird is positioned at an average height of 1200 millimaters (4 foot). Vee shall also assume zat zie bracket holding zie reflector keeps zie light mounted at a distance of 100 millimaters (4 inches) above zie cage top and zat zie light need to be vissin 175mm millimaters (7 inches) of zie bird to have zie optimum effect. So vee can determine from zis information zat your bird vill be at an average distance of 28 inches from a light zat he needs to be vissin 7 inches of to gain zie optimum benefit. To solve "Dana's Dilemma" vee shall use my Inverse Square Law for zie Intensity of Light. Zis law of physics states zat if vee double zie distance of zie light source from a given point zat its intensity vill drop to a quarter of vot it voz originally (2 squared equals 4) and if vee triple zie distance zen zie intensity vill drop to vun ninth (3 squared equals 9). In "Dana's Dilemma" vee are actually quadruple zie distance (28 inches divided by 7 inches = 4) and zearfore zie intensity drops to vun sixteenth (4 squared = 16). From zis vee can deduce zat Dana vill need to mount sixteen lights from zie top of zie cage to solve her Dilemma. I am sinking zat zuch a vast lighting array vould consume a large volume of electricity, but at least Dana vould have a magnificent new chandelier in her dining room. I hope zat zis information has helped you vith your decision Dana".
Back to reality, Dana if you wish to add more light to the area where your birds are positioned I would us a standard floor-standing lamp with one of the new LED globes. These globes cost virtually next to nothing to run and one or two will provide enough lighting to illuminate the area. Providing your birds are on a quality pellet-based diet, such as Harrison's or Roudybush then your birds will be getting ample vitamin D & D3. If not then put a liquid supplement in their water once a fortnight. Vetafarm's Calcivet is a good one, but I'm sure that there are many produced by US based manufacturers that are just as good. I sincerely hope that you found this a fun way to address this issue using the laws of physics which are impartial and therefore cannot take sides in a discussion or debate.