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"The Ornithophobia Diffusion" is the ninth episode of the fifth season of the American sitcom The Big Bang Theory. The episode first aired on Thursday, November 10, 2011.[1]


Sheldon faces his phobia of birds. Meanwhile, Leonard and Penny try going to a movie just as friends.

Extended Plot[]

The episode starts with Penny returning from The Cheesecake Factory and running into Leonard downstairs in the apartment building as he is checking his mail. They have a friendly conversation where Penny asks whether Leonard knows how to cook salmon, to which he replies "not really". Penny asks what Leonard's plan is with Sheldon for the night. Leonard says they were going to watch Star Wars on Blu-Ray. Penny mentions that he must have seen the movie a thousand times and Leonard replies that he has only watched it twice on Blu-Ray. Penny tells Leonard she was going to the movies tonight and asks if Leonard wants to go with her. A confused Leonard asks if it is okay for them to do that since they have not spent any time alone together since they broke up. Penny says it would not be a date, but merely just a man and a woman hanging out and not having sex at the end of the night like a lot of Leonard's dates.


Sheldon trying to scare the bird away.

They reach Leonard's apartment and hear Sheldon yelling, "Oh, Dear Lord, get away from me, you monster!" Penny wonders what it is about and Leonard suggests Sheldon is smart and crazy enough to create a monster. When they get into the apartment, they found Sheldon freaking out over a black-throated Magpie-Jay (called a "Blue Jay" by Sheldon) perched on the window sill, trying to shoo it away. Penny is amazed that on top of all the things Sheldon fears, he is afraid of birds. Sheldon explains that it is called ornithophobia and that someday it will be recognized as a true disability and the landlord will be required to put a giant net over the building, adding that he has fear of nets too. Penny asks Leonard again if he wants to go to the movies with her and he immediately says yes. Penny leaves the apartment as Sheldon continues to try and shoo away the bird. Leonard tells Sheldon to ignore the bird so Sheldon pulls the curtain to cover the window, noting that it is a good idea since attention is what birds want. The bird makes a sound and Sheldon starts freaking out again. Sheldon continues his attempts to shoo away the bird, this time by mimicking a cat's meow, but to no avail. Leonard comes out all dressed up to go out with Penny. He asks Sheldon what he thinks of his outfit, stressing that he does not want to give an impression to Penny that he thought it was going to be a date. He ends up going back inside his room to change as Sheldon decides to call Animal Control, but they just laugh at him. Sheldon draws a cat's face on a piece of paper and attempts the cat meow sound again, resulting in another failure. Meanwhile, after changing his outfit again, Leonard finally dressed up like how he used to dress up everyday to work.

Howard with gadget

Howard assists Sheldon with his "bird death ray", which emits an ultrasonic blaster.

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Leonard and Penny try hanging out as friends.

At the movies, Penny wants to watch a Jennifer Aniston movie, but Leonard wants to watch a documentary on building a dam on a river in South America. Penny insists on her choice and Leonard almost gives in until he tells her that he should pick this time since in the past they always followed Penny's choices. Penny did not realize that and thinks Leonard loved all those movies. Leonard confesses that he only went along with them since he was expecting sex at the end of the night and, since this night was a non-date and sex was off the table, they should watch the documentary. Leonard even asks Penny to pay for her own ticket.

Penny meeting Kevin

Penny meets Kevin.

Back at the apartment, an impatient Howard and Raj are waiting for Sheldon to finish his work on his ultrasonic blast machine before starting the Star Wars movie. Howard says he will just start the movie since, if they wait any longer, George Lucas may change the movie again. Sheldon asks Howard's assistance to finish setting up the machine and, while Howard works on it, Sheldon shares his ordeal with birds with Raj, which includes a parrot calling him a "fat-ass". Howard finishes working on the machine, calling it Sheldon's "bird death ray". Sheldon tells him that it is not a death ray and, if he did have one, he would be in his lair, enjoying the money the people of the Earth gave him for not using it. He starts the machine, but it does not scare the bird away, instead shattering the window. Raj comments with "that is one tough birdie".

Penny and Leonard are hanging out at Brady's Beer after the movie. Leonard suggests that Penny enjoyed the movie since she teared up when the village got flooded and the people had to relocate. Penny denies it, saying she only teared up because she was thinking how come the people could leave yet she could not. Leonard laughs and asks Penny if she would like some French fries since he was getting some for himself. Penny says no and Leonard asks again by saying that she always says that, but ends up eating half of his fries. Penny says that she only ate the "little crispy ones" that Leonard does not like, but he says he likes them and prefers to save them for the end, but they are gone before he can eat them and he kept quiet about it. Penny interrupts, answering that he was expecting sex at the end of the night and Leonard agrees. He asks again if Penny would like some fries and she says yes. Leonard says "great" and asks her for money for her fries. While he goes to get their fries, Penny ends up flirting with Kevin, a screenwriter who is sitting behind their table. Penny even sits at Kevin's table, leaving Leonard alone.


Sheldon wearing Boba Fett helmet and holding a broom.

Meanwhile, Sheldon tries to watch television, but the jay makes a noise again, causing him to get frustrated. Sheldon goes inside the closet and comes out with a broom while wearing Boba Fett helmet. He carefully opens the window and tries to shoo the bird away using the broom, but the bird flies into the apartment and lands on Sheldon's spot on the couch.

Back at the bar, Penny tries to sound intelligent by telling Kevin about the documentary she just saw about generating electricity and preserving the environment, while Leonard sits alone sulking. Leonard finally stands up and asks to speak to Penny. He tells her that he knows she is going out of her way to talk to that guy because he said that their outing was not a date. Penny says she thinks the guy is cute and tells Leonard to talk to other girls if he wants to.

Back at the apartment, Sheldon enlists Amy and Bernadette's help to get rid of the bird. Amy asks Sheldon what he expects them to do and he says that, since they are both biologists, they should know how to deal with living things like the bird. Bernadette tells him that she specialized in microorganisms while Amy studied brains. Amy adds that neither of them minored in bird-shooing. Bernadette asks Sheldon to come back into the apartment when the bird is perched on her arms. She suggests that the bird may be someone's lost pet. Sheldon tells Bernadette to slowly and carefully flush it down the toilet. Amy tells him that the only way to get over a fear is to interact with it, just like what he did with the mailman. Sheldon approaches the bird slowly, but backs away. Bernadette immediately yells, "Oh, just pat the bird, you big baby!", prompting Sheldon to stroke the bird. He still insists on flushing the bird down the toilet.

At the bar, Leonard finally finds someone to talk to, a woman named Laura. He lies to her about the stuff he enjoys such as hiking, karaoke, and Jennifer Aniston movies. Penny comes over and apologizes for ditching him. He says he is fine with it and asks her to go away. Penny says Kevin left and asks to hang out. Leonard says that she only wants to hang out with him now that Kevin is gone. Penny asks Leonard what he has been telling Laura about her, but Leonard refuses and asks her to go hang out with other guys there. Penny asks Laura whether Leonard told her he owns two Star Trek uniforms and he wears them even when it is not Halloween. Leonard retaliates by saying Penny thinks Cold War are only fought during winter. Penny responds with that half of Leonard's dirty movie are animated. Leonard replies by asking if Kevin knows that Penny's acting career involved a long-running role as waitress in a local production of The Cheesecake Factory. Penny asks if Laura knows about Leonard's lucky asthma inhaler. Leonard asks Penny to spell "asthma". Penny can't and asks him to take her home. Leonard initially refuses but, noticing that Laura has left, agrees.


Sheldon's lost and found poster.

Meanwhile, Sheldon has overcome his fear of birds and is infatuated by the black throated magpie jay, holding and gazing at it longingly. He asks Bernadette to take a picture of him and the bird, saying he will use the picture on a mug, mouse pad, and calendar. Sheldon starts calling the bird his "little Lovey-Dovey". Bernadette tells him the bird still looks like someone's pet and they should make poster. Sheldon agrees but says the posters should have the words "Is this your bird? Not anymore!", and starts planning the fun things he will do with the bird, including carrying messages to all his enemies. Amy says Sheldon can borrow her cage if he wants since one of her test monkey slipped over a banana peel and broke its neck. Sheldon declines and says Lovey-Dovey will sleep in his own nest which he will retrieve from the window sill and put in his room, but the moment Sheldon opens the window, the blue jay flies out.

Penny and Leonard return to the apartment building and see Sheldon's poster of his missing jay on their way up the stairs, neither looking as if they had enjoyed the non-date. Leonard breaks the ice by saying that they went out, met some interesting people and said horrible things about each other; so it was a magical night. Penny replies that she is not innocent, but Leonard calls her stupid and she calls him an "asthmatic dumb-ass". Leonard admits he crossed a line and apologizes, even adding that his apology is sincere and he is not expecting sex for it. Penny thanks him and apologizes too. Leonard thinks maybe they are not ready to go out as friends, but Penny says she likes the "take-charge and cocky" Leonard. Leonard immediately changes his mind and puts sex "back on the table" saying that he can be anything she wants him to be. Penny shakes her head and says good night. When Leonard enters his apartment, he tells Sheldon he had a weird night. Sheldon says he had a great night and takes off the orange blanket covering what turns out to be the jay's nest with an egg in it, revealing that the bird is female. He tells Leonard that he is going to be a mommy.



  • The TV Critic: "This season has featured a lot of Sheldon on his own. Or at least not interacting with many people. We have seen him playing dice, seeking revenge, obsessing over paintball or a toy train set. Those stories are fine and he remains one of the few characters on TV who can make scenes funny just through his performance... The Leonard and Penny story was pretty good too. Leonard standing up for himself and pointing out all the sacrifices he made when they were dating made for a fun story."[2]
  • The A.V. Club gave this episode a C-[3]
  • IMDb user reviews


  • Title Reference: "Ornithophobia" is a type of specific phobia
    Tumblr lwxn1kG06e1r4t9h1o1 500

    Black Throated Magpie Jay.

    defined as an abnormal, irrational fear of birds, while "diffusion" means the state of being diffused: scattered; spread thinly or wastefully. The title may also rely on using a homophone for "diffuse" (namely, "defuse", which is to make less harmful, potent, or tense). In this episode, Sheldon's bird anxiety gradually diffuses after he comes into contact with a black-throated Magpie-Jay.
  • Chuck Lorre's vanity card.
  • This episode was watched by 15.89 million people with a rating of 5.3 (adults 18–49).[4]
  • This episode aired in Canada on November 14, 2011, with 3.483 million viewers and a weekly ranking of #1.[5]
  • In the United Kingdom, this episode aired on December 22, 2011, with 1.542 million total viewers and a weekly ranking of #8.[6]
  • In Australia, it aired on November 21, 2011, with 1.369 million viewers.[7]
  • Episode transcript [1]

Costume Notes[]

  • Penny wears the "Waterfalls" sweater/hoodie by Lucky Brand with her Cheesecake Factory uniform.


Monica: Okay, everybody relax. This is not even a date. It's just two people going out to dinner and not having sex.
Chandler: Sounds like a date to me.
In this episode:
Penny: Oh, it’s not a date, Leonard. It’s just a man and a woman hanging out, not having sex at the end of the night.
Leonard: Sounds like most of my dates.
  • Sheldon refers to the bird as a Blue Jay although, in reality, it is a Black-throated Magpie-Jay. In his defense, technically, it's still a jay bird. Also, he states, "Age 12: a magpie tries to steal the retainer out of my mouth." Hence, he can recognize a magpie.
    • Sheldon's bird encounters are actually highly unlikely since Lovey-Duvey, a Black-throated Magpie-Jay, is native to tropical Central America, not Pasadena. And a magpie is not native to east Texas, but in the mountainous regions of the western United States.
  • Raj and Howard only appear in one scene in this episode.
  • Coincidentally, the people that Penny and Leonard interacted with in this episode (Kevin and Laura) share the same first names as actors Kevin Sussman (Stuart) and Laura Spencer (Emily), both of whom would eventually go on to become series regulars.
  • Sheldon is the only one who remains in the apartment for the whole episode.
  • Sheldon first revealed his fear of birds in "The Friendship Algorithm" (S2E13). In "The Jiminy Conjecture" (S3E2), Sheldon also mentioned how a chicken got loose and chased him up the big elm tree in front of his house and speaks of running from angry chickens in "The Cruciferous Vegetable Amplification" (S4E2), just as he recounts in this episode that a blood-thirsty chicken chased him up a tree at the age of seven.
  • Sheldon's e-mail is This can be seen near the end of the episode printed on the "Have you seen this bird?" poster.
  • The photo Bernadette takes of Sheldon and the bird is seen in the next episode as Sheldon's profile picture on Facebook.
  • The sudden uproar from the audience after Amy laughs at the end of the line "If you're keeping him, I've got a cage you can borrow. One of the test monkeys slipped and broke his neck. It was both tragic and hysterical." may or may not have been intentional. In the season 5 blooper reel, a blooper can be seen with Mayim Bialik's use of this line, with the exact same portrayal and the exact same audience reaction as the actual episode (though the episode uses a different take under the same soundtrack). In this blooper, Jim Parsons starts to laugh, and then Bialik collapses into a fit of laughter as the audience continues to laugh harder.
  • Second episode where a non-intellectual character attempts to spell a word to prove they are smarter than they seem only to give up on the first few letters; the first was "The Middle-Earth Paradigm" (S1E6).
    • Interestingly enough, both instances involved Leonard being the one telling the non-intellect to spell the word.
  • Bernadette and Amy only appear in two scenes at Apartment 4A with Sheldon in this episode.


Sheldon: Oh, dear Lord, get away from me, you monster!

Penny: Remember, he's more afraid of you than you are of him.
Sheldon: That doesn't help.
Penny: I was talking to the bird.

Sheldon: (triple knock) Go away, bird! (triple knock) Go away, bird! (triple knock) Go away, bird!

Leonard: No, you always picked, and it was always the same, an hour-and-a-half of beach_house|beachhouses in the rain 'til the woman turns around and realizes love was here all along.

Sheldon: It’s remarkable. All that time spent in fear. And for what? He’s magnificent. Oh, dear. I just realized I haven’t offered you a beverage.
Bernadette: (rather happy by Sheldon's attitude of bird feeding) Oh, it’s just like my grandma with her parrot. And after she lost her marbles with her remote control.
Sheldon: My phone’s on the desk over there. Take a picture of us together. Make it good enough to go on a mug, a mouse pad, and a calendar. If you were a dove, I’d call you Lovey-Dovey. Oh. Who am I kidding? This isn’t a moment for strict adherence to the literal. You’re just my little Lovey-Dovey, aren’t you?
Amy: Guess you gotta have hollow bones to get some sugar around here.
Bernadette: (speaks with embarrassment) I still think he looks like someone’s pet. Maybe we should put up posters.
Sheldon: Yes. It should have a big picture of him, and the words, is this your bird? Not anymore.
(Bernadette looked silent with complete anger by what Sheldon had said)
Sheldon: We’re going to have so much fun together. You can carry messages to all my enemies. I can tie a string to your leg and fly you like a kite.
Amy: (with a rather cunning smile) If you’re keeping him, I’ve got a cage you can borrow. One of the test monkeys slipped on a banana peel and broke his neck. It was both tragic and hysterical.
(Bernadette just smiles crossly and says nothing)
Sheldon: Nonsense. No. Lovey-Dovey doesn’t sleep in a cage. No. Lovey-Dovey sleeps in his very own nest, which I’m going to get off the windowsill and put in my room. Isn’t that right, LD? (Opens window. Bird flies out.) No. Where are you going? Come back, Lovey-Dovey! This is your home now! I already ordered 20 pounds of bird feed off of Amazon! He’s gone.
Amy: (mega-fully worried) I’m sorry, Sheldon.
Sheldon: How could he do this to me? Get back here, you stupid bird, so I can love you!
(Amy looks frightened by Sheldon's yell through the window and the screen fades to black)

Amy: (She is not entirely happy) Sheldon, what do you expect us to do?
(Bernadette and Amy turn their heads at the timid and sensitive Sheldon in the doorway)
Sheldon: You’re biologists. Biology is the study of living things. That’s a living thing, get cracking.
(Bernadette and Amy exchange glances for a second)
Bernadette: (she is rather nervous) I specialize in microorganisms, and Amy studies brains.
Amy: (she's scolding at Sheldon indignantly) Yeah, neither of us minored in bird-shooing.
Sheldon: (he is extremely annoyed) Oh, come now. Your undergraduate work must have included a varmints and critters class.
Bernadette: (crossly) Come back in, Sheldon, he’s not going to hurt you.
(She walks up to the top of the couch joyfully)
Bernadette: He looks friendly. I think he might be someone’s pet.
Sheldon: No, Bernadette, don’t be a hero!
Bernadette: Oh, he’s a sweetie.
Sheldon: Yes. It’s very sweet. Now, slowly and carefully, flush him down the toilet.
(Bernadette ignores Sheldon and admires the bird, Amy now gets more crosser at Sheldon)
Amy: Sheldon, the only way to get past this fear is to interact with it. Just like you did with the mailman.
Sheldon: Every year tens of people around the world are killed by birds. I’m not going to be another statistic.
Bernadette: Look how sweet he is. Come over and say hi. Come on. You can do it. Don’t be scared. Come on.
(Sheldon starts reaching for three seconds, he then put his hands on the top of his heart and sighs with fright as Bernadette now yells at him angrily for a second)
Bernadette: (she is so extremely cross) Oh, just pet the bird, you big baby!
(Sheldon now reaches to give the bird a tiny stroke)
Sheldon: (he's sighing with excitement) I did it!
(Amy smiles reactingly)
Sheldon: I actually did it.
(sighs for three seconds and bosses Bernadette)
Sheldon: Okay, now flush him.
(Bernadette just glares at Sheldon crossly at the 'flush him' order that he has given her).

Howard: I'm pushing "play"--I mean it; yeah, if we don't start soon George Lucas is gonna change it again.

Raj: I really don't get your problem with birds.
Sheldon: What the question you should be asking is what is their problem with me?

Sheldon: (on the phone) I'd like to report a dangerous wild animal. A blue jay. I'm sorry; this is Animal Control. I don't understand the laughter.

Sheldon: Humming bird are the vampire of the flower world.

Sheldon: Age 7: a bloodthirsty chicken chases me up a tree. Age 12: a magpie tries to steal the mouth retainer|retainer out of my mouth. Age 16: a parrot in a pet store calls me "fat ass". Need I go on?
Raj: Yes, please, this is way better than the movie!

Howard: I have a master's degree from MIT.
Sheldon: Yeah, but you got a can-do attitude, and that's what's important.

Raj: That is one tough birdie.

Sheldon: It’s called ornithophobia. And someday it will be recognized as a true disability, and the landlord will be required by law to put a giant net over the building. Which is unfortunate, because I have a fear of nets.

Penny: Oh, it’s not a date, Leonard. It’s just a man and a woman hanging out, not having sex at the end of the night.
Leonard: Sounds like most of my dates.

Sheldon: Bird in the apartment! Bird in the apartment! (sees the bird standing on his spot) No!