Wondering what is in that 'herb' mix that is so relaxing and enjoyable the birds want to nest in it?
Many herbs repel bugs so that would be my guess.
From their site
http://www.twinbeaksaviary.com/herbsalad.html
Red clover leaf & blossom Trifolium pratense
relaxant, antibiotic, inflammations, minerals, potassium, calcium
Echinacea herb Echinacea angustifolia
antibiotic, antiviral, anti-inflammatory, stimulates immune system, vitamins
Chickweed herb Stellaria media
C, B, D, Anti-inflammatory, aids digestion, respiratory
Dandelion root & leaves Taraxacum officinale
stomach, vitamins, potassium, calcium, kidneys, aids digestion
Plantain leaf Plantago major
kidneys, appetite, diarrhea, anti-inflammatory, heals wounds
Thyme leaf Thymus vulgaris
antibacterial, kills & expels worms, diarrhea
Garlic flakes Allium sativum
antifungal, antioxidant, fertility, heart
Oatstraw tops Avena Sativa
calcium, magnesium, yeast infections, thyroid
Yarrow flower Achillea millefolium
blood, supports liver function, virus & fungal inhibitor, tonic
Licorice root Glycyrrhiza glabra
expectorant, supports liver function, anti-inflammatory, yeast infections
Milk thistle seed Silybum marianum
protects liver health, heart, lungs, circulation, worms
Kelp granules Macrocystis pyrifera
iodine, thyroid, stimulant, mucous membranes
Elder berry & flower Sambucus nigra
respiratory, anti-inflammatory, blood, appetite, improves heart health
Wheatgrass Triticum aestivum
circulation, amino acids, enzymes, chlorophyll
Lavender flower Lavandula angustifolia
aids digestion, essential oils, stress, metabolism
Astragalus root astragalus membranaceous
strengthens resistance to disease, digestion, energy, kidneys, stress, diarrhea
Marshmallow root Althaea officinalis
wounds, calcium, diuretic, demulcent, tonic
Spirulina powder Spirulina platensis
fertility, growth, stress, color, protein, antioxidant, improves digestive health
Barberry root Berberis vulgaris
respiratory, blood purifier, detoxifier, supresses Candida overgrowth
Olive leaf Olea europaea
feather problems, immune support, fights infection, anti-parasitic, tranquilizer
Pau d’ arco bark Tabebuia avellanedae
blood cleanser, fights infections, liver, candida, feather/skin problems
Wormwood herb Artemisia absinthium
liver, aids digestion, appetite stimulant, worms